95 Regal (custom) hesitation/rough idle/not sure but a major problem

Hello Everyone, got a pretty big problem and not sure what it is and how to fix. My 95 Buick Regal has a rough idle/hesitation (not sure what to classify as). Sitting idle in park, you can faintly hear the *miss* in it. You can definately hear it at the exhast as there is a rthymic pattern to it. Stick it in gear and go and it will start to stall and then adjust the rpm's and go. I guess I should note that it has never stalled out from this. Going down the road, you will have certain experiences of what I call knocking. Most noticeably is going down hwy at 60, it will start knocking/rapping. Give more or less gas and the problem goes away. Seems to be right around 3000 rpms. Car has almost 100,000 miles on it. I'm not the best technicican, but I did change the plug wires and plugs to no avail. Took it to the dealer to get ripped off for $50.00 for a *computer diagnosis*, they said that it was definately the coil packs. Replaced all three. No dice. Guess I should mention also that the check engine light is NOT on and hasn't been. Yet the problem definately persists. It sounds to me like it's timing, but then again I'm not the automotive's best. I would like to fix it myself as I don't trust any of the dealers in the area (live south of pittsburgh PA - specifically uniontown :o( but I'm not sure what the problem is and if I can fix it. Reading online tells me it could be MAP, CAM/CRNK snsr, EGR, etc. I don't want to have to just start replacing to find the problem. Anyone have any ideas? I wouldn't mind paying someone to do it if they knew what they were doing and could fix it straight out, but so far I've been ripped pretty good. BTW, engine is 3.1L (VIN M) if this helps. Please help, thanks!!

You have already changed the plugs and wires and coilpacks. No codes but still runs like crap. It does sound like a timing problem or fuel, but since both are controlled by the ECM and it is throwing you no codes, Your E-PROM or the entire ECM could be bad. does it spit all sorts of black smoke out?

Nope, no black smoke. Also, regarding the computer, let me elaborate, I don't know what codes may be stored. When I took it to the place I bought it, they hooked it up and said bad coil packs, so I changed them. If there were any other codes, they didn't tell me. From what I've read about this, if it spit out any major codes (like a 41 or other major sensor failure), it would have turned on the check engine light, and this never has appeared (even verified that it does come on when i turn the key on, so the bulb isn't burned out).Are my assumptions wrong about the check engine light (only turning on when it actually detects a failure?) Do I need to spend the money and have someone check the comp again? Personally, I think it's a bad sensor somewhere in the mix (MAP, CAM/CRNK, EGR, etc.), it's not enough to cause a fault, just enough to cause the car to run like crap. I'm basically at wits end.

Oh ya, more food for thought, tried running premium fuel, no dice. Tried injector cleaner, no dice. Time to trade it in?

your car would not throw a code 41 or anything like that, it is OBD II. Im not to fimilar with OBD II yet, Im still learning. This is a thread for flatrater. Sorry, I thought that they did not use OBD II untill 1996.

i think i'm confused, the car is obd I according to the emissions sticker, i was already down that path, sorry. i'm probably wrong about the codes. i agree, flatrater seems to be da man regarding this and his posts. he's from pa too, maybe i can drive the car to him and he can give it a good kick and all will be good!

I guess maybe I should clairfy. I took it to where I bought the car, and they were the ones who did the diagnosis. They are not a GM garage, but I bought a warranty with the car, and it specified I had to take it back to where I bought it. They told me electronic parts are not covered by the car warranty, told me the coils were the problem and the cheapest alternative was to fix it myself. So I tried.

*CENSORED*
My apologies to anyone who was offended.

I have edited my post to you! Maybe I should of sent you a PM first. No offense taken . So let me think about your problem and see if I can come up with something.

Not much in the way of TSB's for your condition.

One major problem GM is having is trying to keep the injectors clean. First thing I would try is a good injector cleaning. You can start with a bottle of additive for your tank but sometimes it is necessary to disconnect the fuel system from the injectors and run the cleaner thru a pressure pot to clean them.

Now the biggest thing I see is your engine knock above idle could you explain it some more? It could be a carbon issue in the cylinders causing this. Have you tried running a higher octane in your engine? Have you replaced your fuel filter in the last 2 years?

With your kinda mileage I would like to clean and reset the IAC! This will improve idle quality.

Usually an idle miss is caused by a fuel problem and off idle misses are caused by ignition. It is kinda hard to help not being able to hear see and drive the car.

Usually when I get a high mileage car I need to do some reccomended service work, its not cheap but I have to have the car's sensor data streams in range of where they are susposed to be.

I want you to remember that the crank sensor is used to start the car and the cam sensor takes over after the car is started. So that usually rules out the crank sensors, you have 2 crank sensors on your engine.

1995 was a weird year for GM cars, some cars are OBD1 and some are OBD2, and the rest are a hybrid OBD2. What color is your PCM? If its black its OBD1 silver its OBD2 or the hybrid. There has been some calibration changes to the OBD2 computers over the years and it could be possibly that a newer program would fix your car.

I could write a long list of things I have seen that could cause this problem but I don't think it would help you much.

First, I want to say thank you for taking the time to look at this and respond. I am definately at the end of my rope with this.

I did run the fuel injector cleaner through it, using lucas fuel injector cleaner from autozone. no dice. can you recommend a specific brand and procedure? tried running highest octane gas, still no dice. don't have a clue on how to disconnect the fuel system from the injectors and run the cleaner through a pressure pot to clean them, but i'm totally open to the idea, is this something i can do and exactly just how to i do this. I'm guessing i mix gas and additive in a tank, pressurize, hook up to the fuel rail (? not sure where and how) and then fire it up??

haven't replaced the fuel filter, i can't remember why, i think it was hard to get to or something. it's been a long ordeal, i'll look at alldatadiy.com again and try to do that asap.

the engine knock is hard to describe. going 60 down the highway, if my foot is on the peddle in a certain place, it's starts "knocking" (maybe i'm using the wrong word here.... rapping, rymthic loud noise). let off or give more gas and it goes away.

need help again with the iac, what is it and can i reset it?

it's definately obd1, connector is black and it says obd1 on the emissions sticker.

remembered iac, looked the procedure up on alldatadiy.com, I think I can handle it. also remember on the fuel filter, couldn't figure out how to "Safely" bleed off the pressure. any tips?

thanks again!

You can bled off the fuel pressure on the fuel rail. The rail has a cap somewhere with a valve core on it, just depress the core till no gas comes out.

The injector cleaning I talked about uses a mix of gas and a detergent which if allowed to go to the fuel pump can ruin the pump, that is why the system needs to be disconnected.

Injector cleaners that work contain TEC. TEC is a strong detergent, not all cleaners have it. TEC is banned in California. I use the GM injector cleaner or a product the BG products makes. BG products are only sold to service shops and dealers, you would have to shop around to find a shop that uses it.

The knocking still puzzles me!

thanks for the tip about the fuel rail. i am going to change the fuel filter this saturday. from what I have found, it only has one filter, it's inline back by the sending unit?!?!

i looked up bp products, it seems their fuel system cleaner is "44k". is this what you are referring to?

the knocking accompanied the rough idle, so somehow they are twisted together.

your tips about the fuel system have me wondering if the fuel filter is partially plugged/injectors are filthy and the car just isn't getting enough gas. guess i'll know more this weekend.

again, thank you.

I sure hope you get this figured out because I have the same problem! Same year, about 90kmi. I've just started doing all the things you're doing.

I'm just gonna add my opinion on this, but I'm saying fuel filter.

And Flatrater- I dont want an argument, but not everyone is going to like you, and you cant lash out at the fellow members. Regardless of opinion on the situation, it says in moderator's guidelines that we are not to have heated arguments with members. I understand why your upset, and I've been upset by some things on here too, but you've just got to live and let live.

[forrest gump] Thats all I have to say about that [/forrest gump]

I just went through all the basics: compression 185 to 190 psig, sparking good (replaced plugs anyway), wire resistance good (3 to 6 kohm), fuel injectors firing, fuel pump good steady flow, replaced fuel filter, sprayed carb cleaner all over intake and found no vacuum leaks, cleaned throttle body, replaced air filter. Spark plugs had grey/white dry deposits; suspect slightly rich mixture or improper timing. Unfortunately, I can't adjust timing on this computer controlled vehicle. My next thought: the timing chain.

sorry my post has been delayed. unfortunately, i as well as autoforum [from my reading] am still having the same problem :o( Big problemo! I changed the fuel filter this past weekend (after a gas bath :o| ) and cleaned the iac as well as sprayed carb cleaner in to the throttle body. the iac was covered in carbon. started the car, and still the problem. i did notice that it did get a *little* better, but nevertheless, the problem is still there. BG Product's 44K is on it's way via UPS, so that remedy is yet to be performed. I sure hope that does something cause I like autoforum am about as frustrated as I can get. I love the car, however I'm wondering if it's telling me in it's own way to trade it in..... More to come after the 44K. thanks again!

That's really funny (so to speak) because I thought mine got a *little* better too after the fuel filter change, but then thought I was imagining it. That started to lead me in the direction of the fuel injectors like bigjess007. That still may be, but I think the problem is as bad as it ever has been. It seems to run better before it's completely warmed up. Anyway, I've found I have other issues with this car (and you probably do too). The valve stem seals go bad but can be accessed by removing the valve covers, no head disassembly required, so I guess I'll plan on doing that some time. Take a look at www.canadiandriver.com/articles/jc/90-96regal_a.htm for a good list. I finally know why my oil pan has been leaking for years! I love the car too and I am inclined to repair it. The Tappet Bros. (CarTalk) always say it's cheaper to repair than to rebuy. My current plan is to take it to a mechanic I am starting to trust and have him diagnose it for $65, but I probably won't do that till mid-April. Fortunately, this is just my "vacation car" and I'm not due for a vacation till June! Let me know about the injector cleaner. Is that the kind that you have to bypass the pump or can it go right through the pump? Thanks, ~Dan [autoforum]

Hello!
I just registerd at this forum today. Just reading your problem with rough idle, hesitation and knock.
I have a 1994 Buick Custom that had pretty much the same symptoms.
I changed and checked everything to do with the fuel and ignition systems. These cars have electronic EGR Valves. I found after taking it apart that there are three spring loaded valves that have to float. Mine were stuck due to heat. I managed to free the stuck valves and it ran better than a new one.
It may be a shot in the dark but you have tried everything else.
Thanks

i'm back, and have no good news with me. i'm currently running the 44k through the fuel system, but the issue is still there. i've only burned about 1/4 of a tank, but i'm sure in the end, this will not solve the problem completely, just make it slightly better as everything else i've tried.

doityourselfer - i'm very interested to hear your story on the egr valve, can you offer instructions, tips, etc. haven't messed with it at all, but i'm sure willing to try it immediately.

my next idea (after the 44k) was to do the tec like flatrater suggested. however, i'm leary to do this as these are the articles i've found relating to tec, flatrater, can you offer your opinion please?
http://www.gnttype.org/techarea/maintenance/cleaner.html
http://www.clubgp.com/cgi-asp/mods.asp?modid=69
http://www.sytyarchives.com/howto/viewarticle.php?article_name=top_end_cleaner.php&dir=engine

thanks all!

Good Morning Bigjess700!
I hope I can answer your questions.
The EGR valve on a 94 Buick 3.1 is located on the driver side of the engine to the right of the throttlebody on the intake plenum. it is about two and a half inches tall +or-. It has three solinoids and a plug in the middle. It is attached with three bolts. On most cars and trucks with a lot of miles on them, the carbon can stp up the air passages into the intake plenum and cause the engine to run rough. I had no faults from this problem.
When you take it apart it should have three stems on the bottom side with three round valves. These valves have to float on the springs. Heat off of the engine can weld these valves to the stems. I was able to free the valves without problem. There will most likely be a lot of carbon buildup on the valves and in the passages of the intake plenum. You should remove this carbon as much as possible to open up the passages. This type of electronic EGR valve is only on the 3.1 according to my manual. The 3.8 has a different type. It serves the same purpose. These EGR valves do pretty much the same thing on all engines. If the passages get stopped up with carbon they can't breath. Its like it's not getting enough air or a vacum leak inside the intake plenum.
I purchased a Chiltons repair manual part# 28682 for 1988-96 model GM cars. It costs about $ 20.00 dollars and is very inforomative.
Also, if the catilytic converter is stopped up it can cause back pressure on the EGR valve causing the same problem.
I hope this helps you out.
Thanks
doityourselfer!

howdy everyone. i'm back, and the "black cloud" is still hanging over me. doityourselfer, thanks for your info, i appreciate it!!! i took the egr out today, and tore it apart. the valves weren't seized up, they were a little ruff though, but nothing major. also, no major carbon deposits. i cleaned everything up, put it all back together, re-installed it, put the key in the ignition, prayed, and started it up. and yep, problem still exhists. however, it did *seem* to make it just a little bit better, like everything else i have done. nothing solves the problem, just makes it a little bit better. so, i'm back to banging my head off the hood <arg!>.

anyway, my new game plan is: i've still got 1/2 tank of gas with the bg 44k in it. so i'm going to run that through the rest of this week. this weekend, i'm going to do the gm tec cleaning. if that doesn't do it, then i think i will start swapping sensors since i just can't think of what else it can be. i'll start with the m.a.p. and move from there to oxygen, etc. if anyone thinks of anything else to do, or that i'm just plain crazy <smile>, please feel free to tell me!!!

on a side note, autoforum, did you take your car to your mechanic yet??

Thanks again everyone!!!

Yes, I took my car to the shop for the $65 evaluation.

I suppose you'd like to know what they said?

Please put your credit card number here: ____-____-____-____!

Just kidding!

They haven't found the problem yet, but I'll let you know what they find.

Until then, I suggest you stop banging your head on the hood and rent the movie "The Princess Bride" or "Pirates of the Caribbean" for some fun! You deserve it after all your pain with this problem.

~the forum

let me tell you autoforum, if they can figure out what it is, and i try it on my car and it fixes it, then you need to give me your paypal account info so i can send you some $$!!! let me say i'm holding my breath for what they find! if you don't mind my asking, how long have they had it? i'm hoping not long as i guess the more time they have it, the worse of a problem it is! :o(

ahhh, on to the movie reviews, haven't seen pirates yet, but the princess bride is a classic!! loved Mandy Patinkin in that flik, miss him as dr. geiger on chicago hope, his character was such a smart a$$ on that series and it made it great. after he left, the show just wasn't the same.

ok, so back on topic, let me know. THANKS AGAIN!

bigjess, I could never do it! Take your $ that is. I feel like we've already shared blood; you've been the only comfort I've had with this problem, knowing someone else can feel my pain! Any help I can give you is only appreciation!

So they've technically had it five days, but since I really liked the guy and the Regal is an extra car, I told him not to rush. I always like telling that to people when I can because if they rush, then I have to take it back! I know for a fact that they didn't start with it until today.

Okay, look, I'm serious about this, you have to see "Pirates of the Caribbean" before I give you any more information! I'm really kidding, I'll let you know about the Regal as soon as I know. But "Pirates" is on the same order of classic as the "Princess Bride", so if you liked that one, you will love "Pirates". We've already got some things in common (don't worry, I'm not a homosexual) and I consider us oil-brothers now, so trust me on that.

Got to go, my break's over.

!Dan

Dan, (and all)
Sorry again for a delayed post, life tends to have a habit of getting in the way. Dan, you too have been a comfort as well and is much appreciated. Only once you have shared someone's frustration can you truly appreciate and feel their pain [quote - someone famous]. True, we do have much in common, cars that are becoming royal pains and a passion for the classics. Which brings me to "pirates." My wife and I watched it this weekend, and both thought that it totally kicked. You were right 'oil brother of mine', that movie rocked!! And their was some kind of funky fate on as when we got done watching it, we flipped the satellite on and low and behold Princess Bride was just beginning on AMC, so we of course had to watch it as well. A weird twist of fate!

Ok, so back on topic. I had originally planned on doing the TEC thing this weekend, however when I got to the dealer on friday (they were having it shipped in), it hadn't arrived as scheduled. After a minor ranting, and much frustration, I left. Called today, still not in. arg! So I'll be waiting until tomorrow and will then become a very disgruntled customer ~:O) If only my swiss army knife and a roll of ducktape would solve this, we would be soooooo good!

Swerving to a side note, is your car losing paint on the roof/hood/trunk lid?

Anyway, I'm going to do the TEC thing as soon as it gets in, and will let you know how that turns out, hopefully by Wednesday at the latest. Hopefully your mechanic is not banging his head off of your car's hood like I as this is a nasty habit! I totally agree in telling him when he gets a chance as it really sets the tone to a mild one!

Later, -jesse

Well I was delaying this post until I had some good information for you. Unfortunately, at this time, I do not! I'm dreading the bill even though it's not fixed yet! They keep telling me that there were multiple problems and so each fix only makes it a little better! LOVE IT! That's their way of getting paid for parts my car didn't need. In a way it makes me feel better that I wasn't able to solve it (since they can't either), but now that's only slightly offsetting the pain of having to let someone else touch my car. Always promising to call me "before lunch", "after lunch", "by the end of the day", "in the morning" and I haven't gotten one call from them in TWO WEEKS! Now I'm calling them four times a day.

So they replaced the spark plugs, throttle position sensor, the fuel pressure regulator, an injector, and then lately the plug wires and it still doesn't run right. When he told me he was ordering new wires yesterday, I asked him if he tried a different set on them to verify the problem: "That's what we do here, Dan, diagnose and fix cars" like he was annoyed at the question. On day 13 I was speechless at that.

Well, I guess my little vacation this weekend is going to be in a Tercel instead of a Regal. I hate to say it, but Jesse, you might have to take yours to a dealer. Oh, and don't tell them not to rush. :|

Well Dan, I'm still trying to pick my jaw up off the desk after reading your post. When your guy made that comment about dianosing your car, and you were finally able to speak, did you launch in to a stream of language that would make a sailor blush? I know I would have, after I was able to utter a sound. Good grief. I can just feel your pain and frustration. Sounds like he's frustrated with the car too if he snapped back at you. 13 days to do what he did, something doesn't sound right, that all could have been done in 2.

I was going to do the TEC this weekend but we had major crappy weather and I held off. When I stopped and picked up the TEC, the part manager wanted to know what I was using it for. I walked him outside and showed him. He said that it sounded like a big problem and walked away. I smiled through clenced teeth!

Well I'm anxiously awaiting your next post. I can honestly say it may be time for me to say adios to my beloved buick depending on what your next update is. Hope your vacation wasn't too bad in your tercel.

-J

Yah, I also had the first thought ever of pawning off the Regal, so sad, it was my parents' car and is so comfortable for long trips.

Well, I had it out with the mechanic today. They replaced the ignition module with no effect. Then he told me that the alternator light came on and is not charging so "I" needed to replace that. When I balked, he said 'okay, we'll hold off on the alternator'. After a night to think about it, I realized that if they kept working on it and didn't replace the alternator my battery would be trashed. Since I have good records and check the alternator every time I change the oil (I have a checklist that I follow every oil service) and I replaced the alternator only 20 kmi ago, I was able to inform him that he owed me an alternator. After quite some heated discussion, he agreed to replace it gratis. I then informed him that I would not hold it against him if he admitted that this job was too much for him and I would pick up my toy and go home. Since he was willing to accomodate me with the alternator and wanted to keep trying, I left it there.

So that's where I am. Apparently this guy is very prideful and does not want this to lick him, so I got to at least appreciate that part somewhat.

However, a bit of good news which I believe, my problem could be more involved than your problem. When he cleaned the injectors and actually replaced one of them, (and I don't know how the plug wires and pressure regulator affected it, but I doubt that the plug wires were a contributor), the car runs much better. My original thoughts were the injectors, and so if I were you, I would pull them out and have them tested. I've never done that so I thought I'd leave that to someone else. There may be more of a problem with them than the TEC can fix. Anyway, that's my thought and I just don't have anything better for you.

I hope you have success soon. If nothing else, you have a friend in L.A. now.

!Dan

Well I haven't gotten the car back yet but today (day 21) I got a call that it's all fixed and runs great. It apparently was the oxygen sensor, to the tune of $552.11. :eek2:

The bill included the probably needed items:
injector cleaning
1 injector replacement

and included the following not needed items:
new spark plugs (I had just installed new ones, and told him that when I brought him the car)
new spark plug wires (they were good as new and did not solve anything when he replaced them)
new alternator (he fried himself and denied it but reluctantly paid (?) for)
new fuel pressure regulator (who knows, it didn't solve the problem though)

Final item was the oxygen sensor which reportedly solved everything. Apparently one of the wires was shorting intermittently and when it did, the operation would drastically change to rough.

I'll post again to confirm or deny the mechanic's findings, but after this ordeal I'll just be happy if the car is truly fixed. The bill is probably less than my time and expense it would have taken to figure it out myself, so I am not too bent out of shape about the cost :bricks1: , though I'm not likely to be parking my vehicle in that garage again.

Bigjess, I'd like to follow up with you but I probably (hopefully) won't be checking this forum so often for a while. We'll have to figure out how to exchange e-mail without putting it in the public domain for junk mail.

Hopeful for another 90000 miles,

~Dan

Dan,

I'm a little late with this post, sorry. I had to pick myself up off the floor. I read that amount and sort of got light headed. :22yikes: Let's jump our conversation offline. Private message me with your email addy (I can't seem to find yours).

I'm so glad that yours is running fine, but so sad that it cost so much. I'm going to run home tonight and look at my O2 sensor. I'm wondering if there is something about the wires running to the 02 sensor that caused them to maybe melt. I sure hope a roll of electrical tape wouldn't have fixed your issue. Although I myself paid once paid for a $400.00 fuse (long story, I can laugh about it now, it really wasn't funny when it happened). I'm sure everyone is looking forward to your final post and I'm looking forward to chatting offline. :thumbsup:

Later, Jesse.

Only in the Buick forums could we get two people who have the same problem, and become such good friends.

AF Buick Forums: Making Miracles Happen, Daily.

LOL

Yes, it is fixed! I chewed the guy down to $472; and after three weeks of losing sleep over my Regal, he really liked the $15 off coupon that I presented to him with my credit card.

Bottom line: O2 sensor. He conveniently lost all the old parts including the plug wires. Okay, so I learned my lesson to take it to the dealer next time.

Over and out.

you better not be out!!!! You're gonna stay here and continue posting!