I have a 1989 350 auto IROC that is giving me fits. Sometimes it will run fine, other times without warning it runs horribly or won't start at all. Any help would be greatly appreciated! A little history, in case this is relative: I ordered the car in late 1988, as a "street" 1LE, but it was not delivered with the package. The dealer apparently didn't know how to order a 1LE. I took it back, and the dealer said they would order all of the parts of the package and install them. Getting them to tell me what was installed was like pulling teeth. I have a feeling they brought in another 1LE and swapped parts to my car. I know they changed the exhaust system and rear end/ rear brakes.


I have noticed the sound it used to make for several
seconds when the key was turned to ON is no longer there
(sounds like the fuel pump is pre-pressurizing the fuel
system)

There are several things it has been doing randomly, or
only once, then the problem goes away:

-Long cranking before engine starts.
-Very low idle, 400-500 RPM, for up to a minute, then
suddenly idling normal, if I don't give it gas. Giving
it gas either kills the engine or makes it spark knock
bad (using 91 octane fuel, the highest available in
Phoenix)
-Stalls at idle (at red lights).
-Oil pressure gauge randomly pins high.
-Runs very poorly, as if on 3 cyliners, for a few
minutes after start up.
-Gray smoke from exhaust and strong sulpher smell under
high RPMs.
-Engine sounded normal, but had much less power than
normal.
-Very hard shifts, while driving slowly.
-Starter cranks, but will not start.
-Turning key does nothing, not even a solenoid click.
-O2 sensor code, (no longer exists)
-Currently has a 36 MAF Sensor Burn off fault code, but
the Service Engine dash light is not on. MAF Sensor was
replaced 5 months ago with a GM unit.
ECM was replaced with a dealer supplied "factory refurb"
unit about 10 years ago.