So I've been trying to figure out why my 93 will die on me sometimes. The first time it died, I had been cruising on the freeway for about 30 min, everything running good and cool, temp needle was right in the middle, around 160. I did notice the dash flashed 'sys' a few times, but everything seemed to be running fine and I was close to my exit. So when I got to my exit I pulled off the freeway and as I slowed down for the light the engine just quit. I coasted it through the intersection and got it out of the way of traffic and tried to restart. It wouldn't go. It cranked just fine, just wouldn't fire up. Weird thing is the 'infl rest' light stayed on, but not sure what the airbag would have to do with the car not running... Anyway, after it cooled down for about 15 min, it started up again, and I was off. Then it died again about 5 min later. I've already replaced the ICM thinking that was it, but it still does the same thing. It goes fine when it's cold or if I'm just driving on the freeway, but when I'm in town driving and it gets pretty warm, then I have problems. It seems clear to me that it's temp related, but what else is really susceptible to temperature... the computer itself? I suppose it could be alot of things, but I figured I'd ask and maybe someone has had the same problem... And when it does drive it doesn't seem to overheat or anything, all operating temps look pretty normal.

And how would one tell if the computer needs replacement anyway? And where would be a good place to get one?

 

Have you checked for codes yet? That's got to be the starting point or your just flying blind.
I will tell you about my 93 and the problem I went through very much like yours. It started stalling at random times and I couldn't see a pattern on what would cause it to happen. After setting 5 minutes or so it would refire and run great. I took it to a friend that has a great scanner and pulled the codes. We replaced the parts and it seemed to be fixed. The problem reappeared and check for codes and nothing was showing. This went on for a while sometimes showing codes and sometimes nothing. In the end I sent the ECM to have it checked and it had a short. That was rebuilt and reinstalled then I found out the MAP sensor was bad. Until the ECM was fixed I couldn't know for sure what was really happing with the motor.
I hope your problem gets resolved much faster and easier than mine.

A little added info. I thought my problem was heat related because later after this went on a while it would get to a certain engine temp and die every time like clock work. This is what made it so hard to pinpoint it would do different things and some different codes as this went a long. You have to have a starting point and that's pulling the codes. If your ECM is bad it can be rebuilt and I think mine took about 9 or 10 days out and back.

 

Yeah, it's at my friends house now, so we'll check the codes this weekend. I should mention, just for fun, that the last time it died, it was at an intersection right next to a Chevy dealer/service center. I took it as a sign and pushed it into their lot and let them have a crack at it... 2 weeks later and I picked it back up because they couldn't figure anything out... they said the codes that it was throwing were 'too vague' and that the car was too old and they didn't have the right equipment to test it...

Sad when a Chevy service center can't fix a Chevy...

 

My 92 had a strange problem - died at random intervals, seemed to be heat related. After it sat a while it would restart but if it was not totally cool it would stall again after 10 miles, 5 miles, 2 miles, proportionate to how cool it had gotten. It stopped being funny when it died on I-40 30 miles east of Amarillo TX in 102 degree heat!

I'll skip all the various things we went through. It turned out the "sock" filter at the end of the fuel pickup had come off, apparently a couple years ago. The orifice on the pump got so plugged with crud the motor would overheat and cut out.

Not saying yours is that, but FWIW it's worth filing in the back of your memory.

 

Looking for codes always helps:

http://www.gnttype.org/maint/malf.html

 

Very sad indeed and seems to be a very common problem theses days

 

I presume that you put heat-sink paste on the back of the ICM when you installed it.

My random-die issue turned out to be the ECM. Got it rebuilt and no issues since.

 

I just realized I hadn't replied to this, but the problem was the Opti. At first it was just causing a hesitation, but then it got worse and was causing the engine to cut out at various times. Pulled the old Opti and it was full of rust powder, I'm shocked it ran as good as it did in that condition! Anyway, put a new one in and it purrs like a kitten now. Love this car!!

 

Thanks for the update and glad you found the problem.