I have a friend with a 88 GTA Trans Am. He bought this car used, and it has had the engine re-built. Its a 305, TPI. I dont think there has been any mods to the TPI system.

Problem:

The car ran fine about a month ago when he bought it. However it recently started acting oddly. The Car hesitates when you get on it, had a rough time starting and wont get over 4500 rpm, it generally feels like it has lost hp, and power in general, but is able to be driven.

To date he has checked the code on the computer. the computer said error code 36, maf / mass air something or another.

With this code, we went ahead and replaced the relays, the MASS Air Sensor, and the ECM. It still has issues at this point.

Does anyone have any ideas?

All help is greatly appreciated and needed!

-steve

 

did u check for vacuum leak. my car acted similar to what u said i found out that i had 2 major vacuum leaks. one for my charcoal canister and one for my breather hose.

 

whats the best way to check for leaks?

 

Has the fuel filter been replaced?

 

Has the fuel filter been replaced?

 

You can check for leaks with a propane canister. Start the motor, open the valve on the canister and spray the propane over the intake and vacuum lines, when you here the motor come up in rpm's you have found your leak.

 

well after replacing the relays, the mass air and the computer, the ses light did go away.. however, it still didnt perform like it did a month ago when he bought it. however, while driving it, the SES light came on, and the car performed like it should. he got out shut it down, and when he went back to start it the SES light went back off and then it did not perform agiain.

THis occured a couple of times. I checked for vacumn leaks, but it does not appear to be a vacumn leak in my opinion.. but i could be wrong..

any input is appreciated.

thanks.
-steve

 

Maybe EGR valve? When I bought my GTA it would accelerate fine until about 1100 rpm's and then it would stumble thought it was TPS(throttle position), so I replaced twice and nothing, then someone suggested I unhook the vacuum line to it and it fixed the problem no more stumble. EGR is bad so when it comes on it is a big vacuum leak and makes the car stumble.

 

I think the EGR is fine, I unplugged the vacumn line from what i believed was the EGR and it didnt make a difference.. but when i unplugged the TPS Throttle Position Sensor it seemed to run a lot better. is the EGR under the TPI unit in back near the distributor? thats what i disconnected.


I think the car has stall converter issues though in my opinion. It revves really high while driving and kinda holds it there for about 2-4 seconds then shifts to second and spins the wheels, and does it again almost to 3rd gear.

 

Yes thats the EGR in the back of the TPI plenum, but make sure when you unhook the line to it you plug it or it will still be a vacuum leak

 

plug the EGR, or plug the TPI where it plugs up to?

-steve

 

you plug the hose you pull of the EGR, not the EGR

 

gotcha, will do that and let you know.

thanks.
-steve

 

If you just unplugged the vacuum line going to the EGR and didn't plug it, and didn't notice a difference in the way it ran, that tells me you have a vacuum leak somewhere. You caused a vaccum leak when you unplugged it and didn't plug the line. If it still ran the same way with this new introduced vaccum leak as before, sounds like there is a vauum leak already. I'd check the vacuum lines coming from the throttle body to the EGR solenoid, and the one from the solenoid to the EGR valve. Since they're cheap, I'd replace them to play it safe. Same with the lines to the PCV vent on the passenger's valve cover, the PCV valve line from the driver's valve cover to the intake manifold, the line from the throttle body to the charcoal canister, and the one to the diverter valve.

If none of that helps, make sure the intake, runners, plenum, and throttle body bolts are all tight. I had some loose runner bolts one time that caused a big vacuum leak. If all else fails, replace the EGR solenoid, and maybe next the EGR valve. Might also check the vacuum fittings going into the plenum, but generally they won't loosen up.

Let us know if pulling and plugging the line to the EGR solenoid (I'd pull that one instead of the line to the EGR valve) makes any difference. If it does it points to either the solenoid of the valve being bad. You can put it back on and then pull and plug the other line to see which one it is of that makes a difference.

Good Luck, and Have a Great Day!!!


- Vern