I have stalling issues on my 1993 Chevy Corvette 5.7L LT1 w/ auto. It would run for a minute. Then it will shut off all of a sudden. Sometimes, it will fire right back up and stall out again, or it will keep cranking and won't fire up for about 5 minutes or so. I check fuel pump pressure and it was good. It sounds like the common symptoms of a faulty ignition control module. So, I went and bought one from Auto Zone and installed it. It's still stalls out. I checked for spark and there was none when it stalled out. I scanned the ECM for trouble coded. They were 16 & 43. I noticed on the Opti-Spark distributor lead circuit from the ECM, there was a voltage reading of 8.9 volts. It supposed to be a 5 volt reference. I also noticed a low voltage reading of 0.5 volts on the ICM circuit coming from the ECM. Could it actually be a bad ECM that is causing me this grief, or bad ECM ground or bad ECM wires touching each other. I don't want to spend money on a ECM if I don't have to. I want to make sure that I cover all based before I even buy a ECM. If anyone has any suggestion, I would appreciate it. Thanks.

LOOK AT THE IDLE AIR CONTROL VALVE,IF IT GOES BAD THE WON'T IDLE.

Check the throttle position sensor, that was the problem with mine. 

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Thank you.

You hit the nail on the head when you said you lost spark.  Had the same problem with my 94.  Mine turned out to be the ignition module but you have already replaced that.  Look for things that affect timing.  Cam position sensor, crank position sensor, etc.  It could be the ECM, but that's an expensive diagnostic tool.

I have a 1991 L98. I had the same problem. Ended up being the EGR ELEC VACUME VALVE. And ECM.