Have a 93 Z28 LT1 that I'm having trouble with. While driving down the road, the engine just dies like you've turned the ignition off. If I put the transmission in neutral and try restart it backfires, sputters and dies again. If I pull over and wait 30 seconds or so it will start right back up and run like there is no problem.

Background and things I have tried:

This has happened to me a couple of times before when trying to pass an 18 wheeler in a hurry. When I would really get on the gas to accelerate it would die on me. As long as I wasn't doing this and running a normal speed (not over 70) the car never died on me.

Now it doesn't make any difference if I am into it or not. If I do get into it I can make it die like before but even if I am not and cruising along it will die after 20 or 30 minutes. Same symptoms either way. Try to start again right away and it backfires and sputters and pops. Pull over, wait a minute or 2 and it will start right back up and go again.

The car was showing trouble codes 26 and 32 so I checked the vacuum lines and replaced the EGR Valve (what a pain in the butt!), reset the computer and headed back out on the interstate. Up to 70 with no problem. Got into it again and it died. Put in neutral, tried to start while coasting, sputtering popping etc. Pulled over waiting a minute, started right back up and drove back home.

Checked codes again and now I am only getting a 26. I picked up a couple of oxygen sensors and plan to replace them as soon as I get a chance. Anyone have any suggestions as to where I go next?

Thanks.
Tim

 

Sounds like a fuel pump.

 

Drove car again today. Same thing happened. Drove for about 15 miles on interstate at 65 mph and it died at almost the same place it did before. Put in neutral while coasting and tried to started engine again and it sputtered popped and sounded like an explosion. Never straightened out. Pulled over, waited 2 or 3 minutes, started it back up and drove back home. Never died going back but when almost home I got on the accelerator a little and had the hesitation and sputtering/popping. Still only code shown by ECM is a 26.

 

test the fuel pressure. the fuel pump can work and when it heats up it will stop. i had a failing ignition control/coil module do the same thing without showing a code. failing fuel pump makes more sense. fuel pressure good and the system works good, less pressure means less fuel but the computer is sending more fuel without anything changing, it thinks the 02 sensors are failing.

 

I went ahead and replaced the fuel pump and still no go. Still having the same problem. The car does start better (starts on first try all the time now whereas before it didn't always start first try).

 

Guess I'm going to try replacing the ICM and coil next.

 

make sure you leave the heat sink grease between the icm and mount.

 

Don't just throw parts at it. Did you check to see if it was losing fuel pressure before you replaced the pump?

A little bit of diagnosing can save a lot of money in parts. Hell it could be something as cheap as a fuel pressure relay.

 

Replaced the ICM and coil and that appears to have fixed it. I have run it approximately 180 miles without it dying on me.

 

good deal, i think the code was caused by the fuel pump so you would have had to replace that anyways. did you use the hatch method? before going with coil per cylinder i carried an extra icm with me, used to drive out in the middle of nowhere so didnt like the idea that it could go anytime. never did again but still. lol