I need some help. I purchased my 89 Iroc a couple months ago. When I first got it, it would start first time every time, and run clean, crisp and idled very smooth even with a mild cam. Since then it has gotten progressivly harder to start, will die a couple seconds after initial start, and often times repeat. it is idling rougher and rougher with time. If it was a NON computer car, I would say it was surging and/or had a low speed miss or both actually. It seems to do this in open loop AND closed loop, hot or cold.

Last week, the mass airflow sensor went, AND the dist was destroying itself and quit firing, which made the trouble shooting even more complicated. We ended up replacing the dist, cap, and rotor, new coil, MAF (Bosch) It is running OK now, but the idle situation is worse than before, but all the same symptoms, just worse. It stalls at lights, turning corners, etc.

I have been reading a lot on the TPI board, and doing several searches for cars that have had similar problems, and while I know a lot about turning wrenches (raced circle track for a few years and was head wrench for a very successful sprint car), but I am NOT up to speed on cars with computers. I'm trying, but in the mean time, I need some help.

Already checked for vacumn leaks --all good--reset timing to spec +1 or 2 degrees, when installed new dist (do not know what timing was before). Disconnected MSD out of system to eliminate--no difference. I have not modified the MAF like the old one was ( no screen + and cut down ). I have a Helm's manual on order, but will be a while before I can get my hands on it.

Can someone point me in the right direction?

 

well,try cleanign out your throlle body and IAC. maybe the ignition coil. could be a number of things,but you can check all that, and the fuel filter.