Thread: 98 Grand Prix GT 3800 159k on it but engine LOPES

Sounds like a vacuum leak. Check all your vacuum lines especially at the t's

bank 1 lean is usually a vacuum leak check then line going into the throttle body
also check the maf
start the car unplug the maf and let us know if anything happens

Originally Posted by RyanL

unplug the maf before you start the car and see if the problem is still there. if you start it and then unplug it it will most likely fordure stall

^this works
but if you do it with the car running we kind find out if the car is running on the computers data tables or if the maf is reading properly

When my maf was bad on my car it just hesitated from a stop. It still idled fine and it threw a code for the maf low input. With the lean code it's almost always a vacuum leak.

Rob..

The two Bill's are here for you on P0171.
Check/replace and or seal the EGR to LIM tube. Typically it cracks over time and no testing will find the leak.
Check all other vacuum and TB gasket etc.
Clean maf sensor
Ensure fuel pressure is good
Check battery cables for any corrsion

That'll start you off.

Lol @ the two Bill's although I am flattered to be included in the same sentence. The battery cable thing perplexed me but that is what finally caused my P0171 to go away and there was no visible corosion on my cables either. Good Luck!

He replaced the whole cables IIRC.

Another thing he found was that even though his EGR tube was good when he pulled back the retaining piece....he RTV'd it to the LIM. Not my usual suggestion, but it fixed a leak for him.

Yes the entire cable is what I replaced.

As far as the EGR leaking it was so stupid of me but I had sparyed enough carb and brake cleaner near the egr and various places to clean a fleet of taxis but it never hit the leak so it never changed the idle at all.
I had GTPSHAWTY on here come over and he was helping me and he was on the forum and somebody and I am not sure who (but thank you very much) suggested plain soapy water in a spray bottle since you can spray that in a tighter stream and beyond when the engine gets hot without fear of catching fire, it was only thru that method was the leak found. My egr tubes are now a nice golden color from the copper rtv that was slathered all over them. It is the little stuff that drives people crazy and even though it was a little leak in relation to say the brake booster or something I could not find it and replaced a lot of the same parts as you plus some in an effort to find what the soapy water wound up finding. Good luck!

Now...he's stuck with one golden clean spot in the engine bay.

I did not know if it was okay to use on the tubes but I looked at the heat ratings of all the different rtv's I have and the copper one was plenty high so it was slathered on. I figured if it didn't work then I would either replace the egr stuff or delete it since I am in Florida aka The Sunshine and Smoky Tailpipe State and we have zero emissions testing. It worked on mine so but yours could be different but good luck again