98 GP GT 3800 na with P0171

[fritcr]

I have been reading for hours on here at all of the horriable stuff with this code. I got the code on the way home several weeks ago and it was either idling or just taking off.
The car was running really rough and sputtering. I got it home and checked for vac leaks to no avail. I finally took it to a garage and he said it was he MAF sensor. We replaced it and it ran fine that day with no codes. Then I took it to the body shop to fix the dreaded gas door rust and it has been there for 5 weeks. I can't imagine how it can take 5 weeks to fix that but whatever. I picked it up and drove it one day and now the p0171 is back. It seems to be running pretty good though. It does seem to hesitate a bit on take off sometimes but bad. It has 145k on it and I have had the O2 sensor replaced and the Upper and Lower intake gaskets replace last year.
What's next? I cleared the code last night and drive it in today and it didn't set the code but I know it will :-(

[richtazz]

First off, what brand MAF sensor did they install? If it's a reman unit from Cardone, there is a good chance the new one is junk. If the MAF proves to be ok, then this code is almost always set due to a vacuum leak. With vacuum running all over the car controlling everything from HVAC mode switching, to EVAP vent/purge, to MAP sensor/PCV operation, it can be difficult to track down. If no other codes are present, then it's time to hunker down and start tracing vacuum lines until you find the issue.

[fritcr]

Well, I know the maf came from O Reillys but not sure what brand it was. I had checked all vac leaks that I could think of before I took it to the shop. I have read this morning about the plastic line going by the battery. I'll check that and look around some more. I have carb cleaner and had sprayed it all around the last time till I was about to gag. lol
I know the body shop guy probably had the stuff around the gas tank filler all undone is there vac lines back there that might be cracked or left off?

[fritcr]

I know this thread is kind of old but I'm still having this problem. I have checked all kinds of stuff since this post. I have checked and traced all the vac lines that I can find. I took the TB off and cleaned and replaced the gasket. I took the egr valve pipe off and checked for cracks..nothing. I checked the Y vac line thing on the intake and it is fine. I also took the PCV valve out and cleaned it and replaced it back in with the o ring. (it looks good and I had already replaced it last year) I also cleaned the battery cables per someone's suggestion.
Any other ideas?
I'm really starting to wonder if I got a bad maf from O Rileys.
Rob

[richtazz]

call your parts source and see what brand they carry. If it's Cardone, there's a very good chance it's bad.

[fritcr]

I think it is a cardone. Should I just ask for another one? I might go by and get one on the way home.
Rob

[danielsatur]

The proper testing for a unmetered vacuum leak is a smoke test, it can pin-point your problem, see http://www.youtube.com/watch?v=FfQ7qWiG-M
Caution - aerosol sprays can be very flamable.

[fritcr]

I did have a smoke test done. They said there were no vacuum leaks that's when they repalced the MAF sensor. The car would hardly run at that time. Now, with the new maf it seems to run good but I get this code off and on. Driving me crazy. I didn't have time to stop at O rileys for a replacement maf afterwork.
Rob

[danielsatur]

If smoke Test passed -
I would suspect the MAF, or upstream H02 sensor.

[fritcr]

I will pick up a replacement MAF today and I have already put in a new O2 sensor also.

[fritcr]

Ok I picked up a new replacement MAF and put it on...the light was actually off when I switched it but came on again on the way home. It is back off now. Soooo that didn't fix it.
Also, sometimes when I start it...esp if it has sit a few days it will "galliup" or idle really weird for a few minutes. It will eventually smooth out. Has done this since I got it.
Any more ideas what I can do or check?

[tblake]

Have you checked for vacuum leaks using carb cleaner?

Does it idle any different if you put your foot on the break and hold it?

What is your fuel pressure?

[BNaylor]

Since this is a NA SII 3800 engine do you have the original UIM plenum, UIM gaskets and lower intake gaskets or have they ever been replaced? The P0171 or P0172 lean/rich trim DTCS are the worst to get and may never be fixed but can be systematically troubleshot and possibly fixed.

Are you getting any coolant loss? How does the exhaust look when you first start it up? What do the spark plugs look like - plug read?

[fritcr]

Hey BNayler and tblake. You all always chime in and try to help me. Thanks soooo much!
Ok money is tight and I have had a rough week last week. (my aunt was killed in a car crash that left my uncle and cousin in ICU for over a week...but anyway..)
Now I can try to work on my gp more. I have checked for leaks with brake cleaner a while back with no change that I could tell. Putting your foot on the brake at idle does not seems to change it. I don't know the fuel pressure but mech checked that and said it was fine. The Upper and Lower intake gaskets were replaced along with the plastic intake thing on the top shortly after I got it. (green was leaking and pooling up around the injectors. As of now I have no coolant loss or coolant in my oil. It runs really well. Actually, it seems to run better since I cleaned the TB and put a new gasket on there. Seems more responsive and got rid of the very slight stumble on take off. The exhaust looks normal on startup. I live in the midwest so you never know what the temp will be...was 71 Sunday and today it is 27 LOL. I tuned it up a while back with new plugs and wires but have not pulled a plug out since this P0171 light.

On a side note...does anyone know how many back lights are in the instrument cluster? I have one burnt out and will go get some replacements today at lunch but would just as soon replace all of them while it is out.

[tblake]

Sorry to hear about your family. Thats never easy. We will pray for you and your family.

On the instrument cluster, if I recall there are 5 of them, but might not be a bad idea to buy 6 in case I am wrong. They are 194's but I upped mine to 168's to make it a little brighter (Bob's little trick).

When you had your LIM gaskets replaced, was there a reason the mechanic replaced the Upper Intake? Was it just preventative maintenance or did he do it cause of a leak. I am wondering if its possible your car was burning a little coolant and it caused your O2 sensor to get a coating on it. You may want to try to get your pre-cat O2 out, wash and scrub it with carb cleaner, and see if that helps. Had this happen in the pickup. A couple intake runners on the LIM gasket blew causing the cylinders to suck oil from the lifter valley. It kept fouling out plugs and also coated my O2 sensors making the truck run lean and ping. New LIM gaskets and 2 new O2 sensors (one for each bank) cured the issue.

Also when was the PCV valve changed last? It may be a good time to also remove the MAP sensor and check the rubber accordian seal.