After just having fixed a rich running engine (MAF sensor & relay) now it's much to lean. It seemed like an EGR problem, cause disconnected, it ran much better. Sooo, we put in a new EGR valve. No difference, still very lean. To the point where the car stumbles as you drive. There is good fuel pressure, vaccuum is good and the o2 sensor reads fine.
Does anyone have ideas or suggestions.
Thanx.

i had the same problem at one point. I did the same thing. My problem came down to a stuck injector wide open. I had to change the injector. if you can't figure the problem out. get it scoped at the dealership.... post here if you find out.

Have you driven many kms since the new parts were installed ?

I was wondering if you had reset the ECM yet ? Pulled the battery connection and then hooked it up again ? Your ECM may have calibrated itself for the old MAF + sensor. It might need to baseline for recalibration to the new parts.

RP.

We did reset the computer. I was hoping that was the problem.
The injectors were cleaned and metered less then 1000km ago.
That's all the mileage that has been put on the car, since a total rebuild. with all new sensors. It seemed to work fine until the MAF sensor burned out. That was caused by the burn-off relay stuck open.
I have the car at a shop right now and everyone says, if this guy can't fix it, no-one can. Well, he's stumped.
He's doing some research on the weekend, so hopefully he comes up with something.
Is it possible the EGR silenoid is bad? At high RPM it seems to be OK. Just can't drive all over in first gear
Thanks again.

This is what I find puzzling.... If the O2 is reading OK, then its not running lean... unless your O2 sensor isn't reading properly. My point is, if its lean, the O2 will give a lean condition code.

maybe the iac valve. Its not retracting to get off idle open loop mode, and running a little lean. high rpms would be ok for gases excaping, but would load up at idle, i don't know, trial and error time for that motor. is it a stock rebuild or upgarded parts, heads cam lifters rockers, larger injectors??????????/

Alot of what I've been telling you, is coming from the mechanic at the shop. I'm just trying to get some ideas to throw at him. He seems like an up front kinda guy, with a high reputation to uphold. But, he is completely baffled at this point and at $64 an hour, I need to have it fixed. SOON.
The o2 reading is puzzling us as well, but everything indicates a lean condition

The engine seems to run better at cold engine temps, getting worse as temp increases. The EGR valve was opening much to quickly and it run better with it disconnected.
It's basically a stock rebuild, with decking work and a mild cam.
Nothing that should affect operation.
Thanks for the imput. It gives me questions to ask about.

I would change the O2 sensor..... also, check the operation of your MAT sensor

i was just gonna throw the MAT at him. you beat me to it.

Ditch the TPI, and go Carb...

Lot less trouble, and a lot more torque...

Good luck buddy, i went through the same thing before I switched. Ended up it was my new MAF sensor. It worked fine then it went bad, when I took it to the shop, it would work fine for them(always works like that).

I ended up giving my car to a mechanic that worked at the shop for a daily driver for 3 days so it would act up for them. But the amount of labour well surpassed the price for the faulty par.

Like I said good luck, and hope your working some overtime...

Dave

At this point, I know you're right. But I have twice as much in parts and labour alone, then the car is worth. NO BULL.
It almost seems like a game. Who's gonna give in first. Me or the car. Believe me, I'm just about ready to cut my loses and let the 17th owner have a crack at it.

well if you deside to unload it please let me know. i could alway use a second GTA.

Hang in there buddy,

If the mechanics "really" know what they're doing they'll figure it out. They just have to go through the "step by step' process. Check one thing, check another, unfortunately this all comes at your expense. Too bad there weren't shops that diagnosed a problem for free, and then only charged you for the parts and labour to fix it.

Dave

LOLL. Wouldn't that be nice.
This guy really seems to know his stuff. Problem is, other then a lean condition when decelerating, he doesn't see anything wrong.
Normal driving, the o2 reading and gas analyzer, read good.
The MAF, MAT, EGR all check out. But it still stumbles, as you drive.
He said he thinks he needs to fool the computer, because of the upgraded cam and the bored out throttle body housing.
Does this make sense? To adjust for a higher A/F mixture.

Have you tried a post on the TPI board? There are some really bright guy's that would likely be able to diagnose your problem.
If you do try a post be really specific (ie stumble a what rpm?throttle position? what's your f/p? what mod's? engine timing?...etc)
Are you certain their aren't any vacuum leak's? at all operating rpm's/temp's. The reason i ask is that in my tbi pick-up I had the same basic problem that you are describing and after much swearing moaning and bleeding finally traced it to a small leak in my EGR diaphram that only became noticeable in a certain temperature/RPM window.............SR