I just got an 86 camaro 2.8l v6. My car has a very rough start and won't idle, it also has a hard time accelerating and backfires a lot. When I unplug the mas airflow sensor the car starts, idles, and runs perfect! I have tried two new mas airflow sensors and still have the same problem. I have replaced: mas airflow sensor relay, fuel pump and filter, spark plugs, spark plug wires, harmonic balancer(it was broken), disturbuter, and air filters. Nothing has worked so far. Someone has suggested to replace the EGR vacuum solenoid, but I am not sure why that would be different with the mas air flow sensor plugged in or unplugged. Any ideas what is wrong or what to try next?

 

has timing chain been replaced?

And everything works fine if maf is unplugged? Are the mafs you replaced it with new,used, reman, etc?

 

To test if it is indeed the EGR... Just remove and plug the vacuum line to the EGR. IT will trip a code but you can ignore that.

Edit-

Actually, on further thought... the only thing that could be wrong with the EGR and cause your symptoms is it stuck in the open position. With the car running, push up on the diaphram on the underside of the EGR. It should move upwards easily, and you should hear the car struggling to run. It may even die. This will verify that the EGR is indeed working.

 

I have tried two reman maf...from two different companies. I figured that they chances were slim that the first one would have been bad but I highly doubt that both could have been bad. The car runs completly fine when it is unplugged...

I have not replaced the timing chain, but I had the timing checked and it was perfect.

I will do that test to check the egr...I'll let you know what I find.

Thank you...

 

Three things come to mind here:

1. Vacuum leak. 2.8's should have around 15" Hg vacuum. Get a vac gauge and take a reading off of the tee in the back of the plenum, near the distributor.

2. Don't get a reman MAF. NEW ones, with a LIFETIME warranty, are $80 at PartsAmerica.com. There is also a fuse that is used for the MAF sensor. Also check to make sure the connection is good and tight at the sensor and the relay.

3. You might have a bad/going bad ignition module inside the distributor. Take it out and take it to an AutoZone, if you can, and have it tested. You can get a GP/Sorenson unit, also with a lifetime warranty, for $40.

If the EGR solenoid was bad and the ECM is good, you should be throwing a code 32 because there is a switch next to the EVRV (the regulator valve) that reads the vacuum signal coming into the EGR valve. You can do the test, but IIRC, the EGR flow won't affect the engine on acceleration. I could be wrong about this, however.

 

I am just not sure why any of those things would be different with the maf plugged or unplugged.
I check the egr and that is fine.
I put in my code tester and got a code 34...it says that it could be the ecm or ckt 528 wiring connector...Do you know any ways to check either of those two things?

 

I think on most or all thirdgens the ECM is located unfortunately by the heater core. If you got a haynes or chiltons manual it will help a lot to remove this and check the connection on the ECM

 

The ECM is easy to get to and doesn't take much time to take it out. My bud did his in about 15min.

 

Just pull the passanger side kick panel (3 7mm screws.) The ECM is right there. Two 7mm screws and it drops down.

You will be able to tell that it is the ECM because of the large number of wires going into it!