Ok my friend 89 camaro RS is having some serisous engine problems. Heres what it does. It idles very rough, if you tap the gas while in neutral at idle, it bogs and tries to die for a second, then comes back up to idle. It is horribly slow, you have to let the clutch out at like 2000 rpm very easily to get it to go, otherwise it lurches and bogs. And it has absolutely NO power. You have to floor it to accelerate at all, even in first. But when the engine revs to about 3000 rpm, it will start pulling alot better. Also, it does not throw any codes.

We do know the previous owner put a new engine in it, the EGR valve has a vacuum line going straight to it instead of going through the EGR soleniod. We don't see any obvious vacuum leaks.

Heres what has been done:
New fuel filter, new O2 sensor, checked fuel pressure (was fine), checked base timing (was fine).


Heres what we're thinking it could be.
1.) A major vacuum leak, probably somewhere out of view.

2.) The mass airflow sensor, because we removed it while the engine was running and it did not change condition at all, except for the fact that it then threw a code since we unplugged the MAF.

What the heck could it be. We are to the point of guessing things. My friend has to have this car working, its his only way to get to work.

 

Ward,

You are probably correct about the "major vacuum leak" theory. And the fact that it is "out of view" should be another clue. The EGR valve must have a solenoid controlled by the ECM. All of the vacuum diagrams I searched for 2.8L engines show an EGR solenoid from the factory, so you really need to take care of that first.

As an interim step, disconnect and cap the EGR vacuum line so the valve remains fully closed.

The fact that you generated a DTC by unplugging the MAF is good, since you have proven that the ECM is still functioning.

Bypass the EGR for now and report back with results, please.

 

Update: We figured out part of the problem. The fuse for the fuel injectors(we think, it said EFI) was missing. It does throw 2 codes when the car is warmed up. It throws code 32 and 34. I assume this is because the car is warming up and trying to go into closed loop mode. It still seems to misfire at low rpm, and jump & lurch in gear, due to the misfiring. Any ideas???

 

BTT - Anyone???

 

My brother has the 2.8 and had a similar problem. After testing just about everthing imaginable we replaced the injectors because we were out of ideas. The injectors cleared the problem immediately. I'm not sure if this would apply to you,but after we went through the entire vacuum system,we replace all the vacuum hoses.complete tune-up,2 different types of plugs,new wires,fuses,fusible links,fuel sender,fuel filter...just about everything and still had the miss when tapping the gas pedal. Hopefully you find the problem before deciding on the injectors,but in our case nothing else worked and it was a last resort.

Niko