Bucking

Hello fellow Lumina owners. I’ve had a problem for about 8-months now and still have not figured it out. My Lumina is a 93 with the 3.8 engine and 133,000 on the clock. When the engine is cold it runs super, no problems what so ever. When it has reached optimal operating temperature it sometimes bucks like there’s a midget under the hood pulling off plug wires. This does not happen all the time only once in a while. Enough to give you the fear of being left along side the road. The check engine light works perfectly but does not come on to indicate a problem. In the winter time it runs very well but the warmer the ambient temperature gets, the more frequently it bucks. So far I have replaced all the plugs, ignition wires, MAF sensor, oxygen sensor and have even filled it with high test and you know that hurt and it still acts the same. I have read of similar problems where it was thought that perhaps it could be the TCC solenoid or the vehicle speed switch. Before I go tearing off and putting on more parts I’d like to get someone’s take on this. Any insight is appreciated.
Thank you

Even though your MIL light is not on does not mean that there cannot be "History Codes" in your computer. With engine running like you describe monitor system should kick some kind of code. I believe Auto Zone ? does scanning. Try this first. Can't Hurt !

Thanks for the tip but unfortunetly there are not any Auto Zones close by. I have taken it to the local shop and they find no history. And of course the vehicle will not act up when it's there. They also said that the system in place does not give detailed information the way the new computer systems do. They say information from the 93 era is vaque at best.

Well my '93 just started recently acting in a way that would accept your description..and indeed I will investigate if it is TCC (will install a switch on the wire) , ignition (but I have no codes indeed) or even CV joints...
What surprises me is that it shows even with a very light acceleration and it seems to do it ..or is more perceptible -- with TCC applied in 3 or 4...
If TCC slips, it should throw a code DTC39...but I think all those who have reported a TCC as culprit never told they had a code.. www.avigex.ca/xport/dtc39.jpg says the condition must exist for 10 seconds...but when that happens, the reaction is to ease the throttle...so the 10 sec is never reached...
I'm not in a hurry though..and the problem is not severe..so a lead may take some time to come.

One more thing that may be of help. When it starts acting up and I take it out of OD and put it in Drive, it stops. It seems that by lowering a gear the problem goes away. Which makes me lean towards a vehicle speed sensor, but who knows?

One more thought also: this engine runs at such a low RPM that I 'm asking maybe, just maybe, after years and mileage, the transmission pump might not develop enough pressure at 1500 rpm/55 mph in 4thTCC...and either kicking it out of TCC or reverting to 3rd increases the rpm and pump would develop enough pressure to keep all clutches..regardless of which, tight and non slipping....and one thing I'll check very soon it the condition of the transmission filter..that I'm due to change anyway....mmm...for years...sooo....ASA new info comes in, will update.
However though, when it starts acting up, I keep an eye on the tach and there is absolutely not even the smallest sign that the rpm would go up....so, TCC or any other slip does not show at all...

Well...it is becoming more and more severe...and as it goes, it seems less and less the TCC is at fault. IN fact I'm leaning on ignition problem...and misfires are just much more perceptible when TCC is engaged. One trick I used is to tune the AM radio off station and turn the volume up. We can hear the ignition noise and there is definitely an irregular pattern ..that is changes in the buzz, when it starts acting.
Since I have a CPSensor and ignition module fresh from last year....I'll start with step one: a set of ignition cables....long overdue anyway, then procure replacement coils. WIll keep updating...

I've allready gone the ignition wire route, along with fresh plugs, MAF sensor and Oxygen sensor. As I wrote before the service light does not come on during these episodes. I am convinced that what ever it is, it's thermal related. It works very well cold and the warmer it gets, the worse it gets. My inspection is coming up soon, I may replace the vehicle speed sensor and see if that makes a difference.

I have a '95, 3.1 Lumina which seems to have exhibited just about all of the symptoms mentioned in these Lumina threads. Thanks to LMP I have just cured the intermittent wiper problem. I am now interested in this thread as this bucking and poor idle etc. is also happening on my vehicle. I had a tune-up done for me which included wires, plugs, etc. This seemed to cure the problem, (I was congratulating myself for being a clever boy), but now the symptoms have returned. Not knowing anything about "codes" or how to get them, (and the Haynes Manual being of no help), I am flying blind and hoping that one of you posters can help me out. Any feedback as you proceed with your vehicles would be greatly appreciated. It doesn't help that the rear wires are hidden from sight, so that anything which might be visible cannot be seen on this car. Thanks in advance.:licka:

DO not loose hope...I'm a little busy at other things right now and I run the Kia Sportage instead since the Transport is almost unserviceable ...still runs but just more than normal throttle brings a lot --A LOT--- of misfire and bucking..whatever the gear..really annoying.
Will update ASAP.

No problem, next month my inspection for the APV is due. I believe I'm going to have the TCC changed at that time regardless. I hope I have some positive news for you at that time.

have you had the coil pack tested??? on my sons it was 1 of the coils in the pack..you should have 3 in the pack.....good luck.....

Yes, and they are fine. I truly believe it's the TCC selenoid, everything I have read points to it and I hope I can share some positive results with all of you.

Thanks for the tip, Scrapper. I'll try check that out tomorrow.:licka:

have you had the coil pack tested??? on my sons it was 1 of the coils in the pack..you should have 3 in the pack.....good luck.....
..my next step in line. I have located a complete package (ignition module and 3 coils) for C$85....and at least I will keep it as a spare even if it does not prove the case. I have changed the ignition module itself..just the wafer...last year...so I'd be mad if it had gone wrong in such a short time but all is possible. But indeed I do suspect one of the coils could be the cause here.
By the way, anyone who has changed the spark plug wires, any tiopon how to get this wire holder that seems stuck under the dog bone ?

Thanks LMP. I would have checked the coils but I couldn't find the bl**dy things. :evillol: I got a Haynes manual but can't find what it describes as a coil under the hood 0f a 3.1. Sooooo...... as my car is now consistently missing on at least one, (maybe more), cylinders and is totally gutless, along with a smell of unburned fuel, maybe it is time I bought a set of coils? At least that way I'll know what to look for. You mention C.$85. LMP. Are you Canadian? If so where did you source the coils from? They're probably available from Canadian Tire but I expect you found something better than that? :iceslolan

Thanks for your help, you people are great and very helpful. Sorry I cannot help you with the dogbone and wire holder problem. Does the holder slip off or screw off the wire at all?

Thanks to LMP I have just cured the intermittent wiper problem. I:licka:

Whats is the LMP wiper problem I have it when my wipers get wet. Obviosly when there needed.

Gimpy....check out the thread "Windshield wipers" started by eVictor. You will find a reply by LMP in which he discusses weak soldered joints on the module attached to the wiper motor. Depending on the model it may be fairly simple to remove the motor and resolder the joints. Mine is a '95, 3.1 and it was pretty simple. An effective repair too it seems, as mine has not played up once since I did it. My trouble is that it is still running very rough. Off to the service station tomorrow for diagnostics I'm afraid, as it is barely useable now..... and certainly no pleasure to drive. Good luck.

.. can't find a coil under the hood 0f a 3.1...where did you source the coils from? ?

3.1 has a single coil....will look for a picture.
I used a 3.8 3-coil set from salvage...proved to no avail...then returned them. IN fact they had come complete with the ignition module that proved itself shot....so no problem returning the whole pack.
Will go to basics first...I assume (..I do not like that..) my ignition module brand new form last year is OK....so a 14YO car can invest in a new set of spark plug wires...right or wrong in a few days down the line...

for wipers check this out:
http://www.automotiveforums.com/vbulletin/showthread.php?t=677547

WOW. Mine is doing the same thing. I just thought that the pistons were trying to swap holes since it has 200K on it. I know that mine is do for a tune up. That is were I was going to start. 200K on the original fuel filter had me thinking that was it. Look forward to finding out what you discover.

..changed three front spark plug wires...and got rid of the frightening part of bucking: still some left, but status has moved from "unserviceable" to "somewhat annoying"
..will see later when I manage to get the rear three in their place.

Sorry, guys, have typed complete response to this thread and watched it disappear into cyberspace. Don't have the time to do it again. had my car serviced. Problems:
1. Bad ignition wire
2. EGR valve not working and losing vacuum as well
3. Throttle body gasket leaking and losing vacuum.

Hope this helps you all.

Sorry so late in getting back with the results of my struggle with the “bucking” problem my Lumina APV 3.8 has been experiencing.

To review my problem was that the engine would miss intermittently in any gear after the engine was warm. I changed the following:

Plugs & wires
Oxygen Sensor
Ignition coils
Ignition Module
Crankshaft sensor
Computer
EGR valve

I’ve taken it to a specialty shop to see if it was the transmission and they report that the transmission is working properly. I then took it to a highly recommended garage and they worked on it checking for vacuum leaks, etc. Could not find any leaks or anything wrong. However they do acknowledge that there is a problem, they just can’t pin point it.

So after all this time and a 1000 bucks, it still has the same condition and no one can figure it out.

RTV...mine turned out to be caused by an arcing rear ignition wire burned on the exhaust manifold, plus a faulty after-market EGR valve. It cost me about $500 but has been well worth the outlay.

I couldly wish it were that simple. I've checked for wiring possibilities and have all ready installed a new EGR valve and still no improvement. My next planed step is to start checking the fuel injectors.

have you had the coil pack tested??? on my sons it was 1 of the coils in the pack..you should have 3 in the pack.....good luck.....


i agrr mine was the coil pack

..my next step in line. I have located a complete package (ignition module and 3 coils) for C$85....and at least I will keep it as a spare even if it does not prove the case. I have changed the ignition module itself..just the wafer...last year...so I'd be mad if it had gone wrong in such a short time but all is possible. But indeed I do suspect one of the coils could be the cause here.
By the way, anyone who has changed the spark plug wires, any tiopon how to get this wire holder that seems stuck under the dog bone ?


how did you make out mine was the coil pack that caused this problem

Well finally the entire problem was with the ignition wires, as stated on 06-21 post...and I changed the rear three wires a little later and this is over...well, say 95%..the last 5% I think is traceable to a slightly worn out CV joint on right side. I made several trips last fall and nothing worsened...and now Transport is hangared for winter...will go out on May 1st. (winter is L_O_N_G around here).

I have all ready replaced the following:
Plugs & wires
Fuel Filter
Oxygen Sensor
MAF sensor
Air Intake Temperature Sensor
Ignition coils
Ignition Module
Crankshaft sensor
Computer
EGR valve
To date I have invested enough time and money that I could have exchanged the entire engine. The problem still remains and no one has an answer. My next step this spring is to replace the intake manifold as they are a common problem with these engines. They leak up underneath where the EGR valve stem enters the intake and cause all kinds of problems. At least that's what is being said on other forums.

...mmm...THis flaw (intake manifold and intake manifold gasket ) is reported only with series 2 3800....which began in 1995 in all GM lines using the 3.8 except transport/APV which kept using the end of line series 1.
http://www.bonnevilleclub.com/forum/kb.php?mode=article&k=38
http://www.automotiveforums.com/vbulletin/showthread.php?t=401247
NOt to say it is impossible, but the odds are negative..