1996 Taurus GL Misfiring/Sputter 6 Cylinder 3.0L

About a week ago I was driving to my girlfriends house and along the way at red lights I could feel it idling rough. I got to her house and the service engine soon light was flashing indicating a misfire. So I drove it home the long way, and red lights it was idling like a semi truck. I got home and today I took it to Auto Zone. They did the reading and said it was a EGR valve, a mass air flow sensor and it was misfiring on cylinder 1. They said I should probably replace the EGR valve as it was clogged/stuck and that was causing problems to the mass air flow sensor and causing the misfire. I replaced the EGR valve today. It's still idling rough, light is flashing still, it doesn't quite feel as bad though. Now I heard also that if it was the EGR valve causing a misfire I should maybe replace cylinder 1's spark plug. Any other suggestions? Really stumped and aggrivated I just wasted 50 dollars for a new EGR valve.

Wind3x

Did you get the code numbers from AZ?

Regards,

Dan

Not quite sure which numbers you'd like I believe these are them.

One slip says, Troubleshooting P0402 (Is the slip indicating the faulty EGR valve.)

Other says, Troubleshooting P0301 (The one indicating a misfire on cylinder 1)

and the last says, Troubleshooting P0171 (The slip saying fuel injector issue/o2 sensor/mas air flow)



If you need anymore info let me know.

Not quite sure which numbers you'd like I believe these are them.

Yep...those are the ones.

One slip says, Troubleshooting P0402 (Is the slip indicating the faulty EGR valve.)

P0402 EGR flow higher than expected (DPFE common cause)

Other says, Troubleshooting P0301 (The one indicating a misfire on cylinder 1)

P0301 Misfire on cylinder 1 (rear bank passenger side) (often caused by clogged EGR ports


and the last says, Troubleshooting P0171 (The slip saying fuel injector issue/o2 sensor/mas air flow)

This group of codes indicate a condition that the indicated oxygen sensor is reporting.


These codes are almost NEVER caused by a defective oxygen sensor or sensor circuit.

P0171 Oxygen sensor reporting too lean condition on bank 1 (rear bank)




If you need anymore info let me know.


I got the code meanings from here: http://www.automotiveforums.com/vbulletin/showthread.php?t=677408

So what would in your opinion be the next thing to replace? Also do you think it's drivable? I have a interview tomorrow.

Wind3x

Sorry I didn't get back to you.....it's tomorrow....did you drive it? How did the interview go?

To check if the EGR ports are pluged. Remove the vacuum hose from the EGR valve and plug the hose with something like a golf tee. This will set an error code. However, if the idle improves then we know that some of the cylinders are getting too much EGR because others aren't getting any.

Regards

Dan

Sorry about the long response I was at training for my job. Interview went well got a job as a PC spec at Best Buy. I drove the car it misfired about the half the time, other half was fine. This was after I replaced the EGR valve. I replaced the EGR valve and the mass air flow went away as did the EGR valve "Check Engine Soon" light problem. It's still misfiring so I took it back to Auto Zone and they say only problem was again, the misfire on Cylinder 1. Told me it's probably a plug/wire. The plugs looked fine and I brushed them off, I started the car, it ran perfect(It wasn't warmed up). It warmed up and it started misfiring. I replaced the plugwires, same thing it misfired. I don't see any vaccuum lines off if that could have anything to do with it. I'm stumped in what it could be, besides a....fuel injector. The weird thing about it is that I'll be going 60 down the road with the light flashing, then you can feel the car fire correctly and it'll speed up to 70+, like the it starts working correctly. Anymore info would be greatly appreciated.

Wind3X

Glad you got the job!

Have you considered the coil pack? I know that they go bad on Windstars. I believe heat can affect them too.

Dan

The people at AutoZone are Idiots and don't know what they are talking about!You could have a bad coil which will cause a miss.It is not the egr that is bad for the egr code,it is the DPFE sensor that is bad.I have seen one miss on a taurus with a bad coil causing the miss.

The people at AutoZone are Idiots and don't know what they are talking about!

Careful making such a broad statement. My Dad went to work at AutoZone after retiring from running his own auto repair shop for 20 years. Prior to that he had spent most of his life working at other shops. He was a tremendous asset to AutoZone (and still is to me). Granted, AutoZone does not require anywhere near that amount of experience to be an employee and there are a few that don't know much about cars.

I'd agree that the misfire is likely due to a bad coil, especially since the problem seems to occur once the engine is warmed up. That's a fairly common way for a coil fault to show up.

-Rod

I take that back and do not ever trust them since being payed about $5.00 an hour and are not certified.AutoZone got in big trouble years ago,tried to charge people for checking codes which was a huge no no.This one I seen with a missfire,the shop they took it to said the engine was junk,were wrong and the coil was junk.Luckily had a good used one on hand and put it in with the missfire gone.

Hello, I was having a missfire on my 2002 42000 mi 24v at idle posted problem and Rod advised me to get NeW spark plug wires. I have always takne Rods advice and BINGO!! put the new wires on and NO More Miss!!
How many miles are on your Taurus.
Good Luck
Rob Roy

Sorry for the long response it's been hectic with work. I went to an Advance Auto near my job after work 2 days ago and the guy there seemed to know more than how to press buttons on a machine. After I had replaced the plugs/wires it was still doing it so he advised me it was the coil so he overnight shipped me one up for free. (My father was very displeased when he seen it had no distributor)

So I went and got it today, came home tonight put it in luckily wasn't bad to put in. Drove it around, the car seems a lot smoother and when I was driving the highway the light would actually stop flashing and would come back in a bit flashing. At red lights on take off where it's normally bad the car seemed smoother. It's still idling rough and I can still tell when the car is misfiring going down the road but nowhere near where it was.

Now my question is, I changed the cylinder 1's plug and it still was misfiring(before putting on the new coil) do you think it could have damaged the plug so that it's not running right now after the new coil? Also, the guy at Advanced Auto Parts mentioned something about it could have a bad valve as well. Would it be doing it all the time and not below 2k rpms if it were a bad valve?


The final thought of mine is, after replacing the egr valve and it still misfiring I tried putting a bottle of STP's water removal in my cars tank(was full tank), and the night before getting a coil I had went and got another bottle of Gumout's High Mileage fuel injector cleaner put in (Not thinking till after I put it in I had 3/4 of a tank of gas). Between the water removal and the fuel injector cleaner I had filled up of about a half tank of gas. I'm wondering could the fuel injector cleaner put in with a 3/4 of a tank of gas instead of full be causing some issues aswell?


I also should tell you that this car had sat for a while as I had bought it for $150 dollars(A steal beings though other than this the car looks/runs brand new) because the owner's daughter had hit a rock and busted the fuel filter and he thought it was the line(a hard 10 dollar fix). Could the car sitting there for maybe a year affect it? Should I change the oil immediatly beings though I've only driven the car for about a month now and put 1k miles on it. Just trying to think of everything/anything that could be giving me trouble, and I'm still trying to understand how the coil didn't fix the problem, only helped it run a bit smoother.


Sorry for the length of absense from my last post and my long posts. As usual any suggestions are welcome and thanks in advance for them, and the previous help. I hope to get through this without having to rip the block apart =/

Also there's 160k miles on it. Edit button on the post seems to be messing with me.

If the check engine light (CEL) is actually flashing and the only code is a P0301, then the misfire must be occuring quite regularly. A flashing CEL means there is a detected fault that is causing increased emissions or potential damage to the emissions system.

What you could try doing is getting an inline spark detector/indicator and seeing if the spark on cylinder #1 seems to be going away when the misfires occur. These are usually available from most of the auto parts stores or Harbor Freight (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97577). If you have the DOHC V6, you'll probably want one like the Harbor Freight (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97577) version since plug #1 will be recessed and not real easy to get to anyway.

If the spark tester indicates a lack of spark at the same times the engine sputters, then you need to keep looking at the ignition system. If the spark seems fine, even when the engine stumbles, then consider checking compression on the cylinders as well as verifying the fuel injector for cylinder #1 is working. There are noid lights for checking for injector pulse which often times can be borrowed from the chain auto parts stores as part of the Loan-a-Tool program.

Check the label on the fuel system cleaners. Usually they indicate the contents will treat from x to y gallons. If 3/4 of a tank falls within that range, you probably didn't harm the effectiveness. With the flashing CEL, it sounds like your car's problem is more significant than a fuel system cleaner will fix.

-Rod
-Rod

Sorry about the length of reply, been working a lot.

So a lot of times when I first start the car it runs perfect and idles nice. It's to the point of I'm so used to the car misfiring the amount of gas I have to give it to go, when it runs find I found myself over throttling the car and burning out, then it misfires and runs slower.

If it were a valve would it do it all the time? I plan on purchasing a spark plug indicator and will keep you guys posted. As usual your answers are appreciated. I also feel like I'm burning more gas when it's misfiring.

Sorry about the length of reply, been working a lot.

So a lot of times when I first start the car it runs perfect and idles nice. It's to the point of I'm so used to the car misfiring the amount of gas I have to give it to go, when it runs find I found myself over throttling the car and burning out, then it misfires and runs slower.

If it were a valve would it do it all the time? I plan on purchasing a spark plug indicator and will keep you guys posted. As usual your answers are appreciated. I also feel like I'm burning more gas when it's misfiring.

Wind3x

Glad to hear that the coil was part of the problem. Have the sparkplug wires been replaced? If not, don't buy cheap ones....they will not last. How about sparkplugs?

I agree with you that a bad valve would be a problem all of the time. If the car runs well some of the time, compression isn't an issue. It sounds like an ignition issue to me. I know sparkplug wire routing is an issue with newer autos.

Dan

Had the same problem with my '97 GL wagon. Without warning, suddenly got the flashing CEL on the way home one night. It would start flashing after driving the car about 2-3 miles. At that point, the stumbling got pretty bad, but it didn't last very long. After about another 5 miles or so, the light would stop flashing and the car would seem to run just fine. Anyway, the code was P0301 - misfire on cylinder #1. So I bought new wires (factory originals were still on the car) and installed just the #1 plug wire (easiest approach first). Problem remained, so I bought new FORD plugs, installed a new plug on #1 and the problem went away. Noticed on the plug removed (the original factory plug with 148k miles on it at the time) that the electrode tip on the end had eroded off at a pretty good angle. My conclusion was this had changed the distance between the "arm" and the tip, rendering the plug bad. Then, almost exactly a year later at 159k miles (a couple months ago), the problem returned. This time I immediately pulled the plug. It was gray and dry like it's predecessor, but no obvious irregularities like before. Still, instead of cleaning it I simply installed another new plug. Eventually I'll get to fixing the underlying problem (whatever it is). I think the car is eating some coolant, so maybe this is the problem. Right now, my theory is these cars develop a gasket problem around cylinder #1 over time.

One question for you: Are you replacing your plugs with FORD parts? I've heard that these cars don't like aftermarket plugs.