sancho

I'm trying to get my '88 Camaro 2.8L V6 (which has been sitting in the driveway for a couple of years, mostly) ready to sell, but I'm having some issues getting the engine to run properly.

Basically, the engine usually starts right up without problems (except that the fuel pump sometimes doesn't prime, but that's a different issue). The idle is generally pretty smooth but, whenever I give it a little gas, it stumbles as the RPMs drop slightly, then gradually pulls the RPM back up. It's really easy to make the engine backfire through the intake if I give it too much gas too quickly. All of this translates in to very poor drivability (it backfires even worse when in gear), and less-than-usual power. I tried changing the base timing a few times with minimal luck.

Today, I put a fuel-pressure gauge on it and noticed that it reads about 43 PSI at idle (and it maintains this pressure well after the engine is turned off). I noticed that, when I tried to give it gas in idle, the fuel pressure increases right as the engine begins to stumble. The pressure then lowers as the engine speed picks up.

The car has a brand new distributor cap, rotor, wires, and mass airflow sensor.

Any ideas what the culprit could be?

pairtoe

iTrader: (4)

vaccum leak, had almost same exact problem with my car. at first i thought it was a timming issue, so i would advance and retard it to find a got spot, but then i noticed that one vaccum line wasnt hooked up, now it runs fine.

sancho

Yeah, that was about the only thing I've not tested directly since I don't have a vacuum gauge. Incidentally, we've suspected a vacuum-related problem with this car ever since we've had it (over 6 years) but never traced it to anything.

Any hints on where exactly to look?

pairtoe

iTrader: (4)

well this might be dangerous, but my uncle is a crazy a-hole and will do anything, but he stuck his hand on the end of the throttle body with the tube off but everything still plugged in(while the car was back firing and blowing smoke a flames out the throtle body!) and he noticed it was not sucking anything in. then we stopped the car looked around the vaccum lines, and found one by the canister not pluge in, pluged it and started it again no back firing, he stuck his had over the throttle body and it sucked his had right to it. problem solved. it will probally be alot more acurate to get a vaccum gauge, but this worked for us.

noahTHEpurdy

iTrader: (1)

Your uncle sounds a lot like my dad. He always tells me ; "If you don't have the ***** to lose a hand fixing your car, you don't have the ***** to drive it.".

He also thinks that jack-stands are for *******.