Okay, so here's the deal. I just bought a 1994 Firebird trans am. 5.7 lt1 The car has 123xxx Supposedly the engine has 10,xxx but I'm not sure. I got it two weeks ago. And has been great!!!! Until recently I was driving and it cut out. I pulled over And About 2 minutes later it fired up fine and drove regularly with no problem. Later That evening. I happened again. Once again, waited About 2 minutes and fired right back up. This time 10 minutes later it died again And I had to wait About 15 minutes. And it kept happening until I made it home. I replaced the coil. And it ran perfect for About 45 minutes. I drove it enough til I was confident it was fixed til.That night the weather was About 65. But I drove it long enough for the car to get hot I drove it to school this morning no problems After school. No problems. I drove it for about 10 minutes. It died.. after it died. It fired right back up. Idled for about 30 seconds And died. Happened 3 times.. I checked to see if it was getting any spark. And nothing. No spark. I read something About an icm, so I replaced that. The car drove the whole day, I drove everywhere that day, ran fine. Then that night on my way home, it shut off, onvce again no fire…..
The car will idle for 2 days without dying. Lol.
So basically it happens when driving.
Checked most connectors I could find.
All seem good.
Grounds seem good also. (actually couldn’t really find many at all)
I added 2 grounds, One from battery to frame and 1 block to frame.
Theres the whole story, it happens when driving. Its happened from a stop then when I go to take off it happenes.. like I said, sometimes it will go the whole day driving good but others itll drive 10 minutes.

please help!
like i said, new coil and ICM
the opti also looks brand new but but i dont know f it actually is.

 

Any codes? Possibility of a crank sensor or opti-junk failing.

 

Yep, I bet it is your Opti. And I bet your water pump has been leaking on it. That was a big problem with the LT1's. The water pump starts leaking and the water pump is right above the opti and ruins it. SO, replace the water pump when you change out the opti if that is indeed the problem.