I've been haveing issues with my 93 z28 for a while now. When i drive it around the block sometimes it does fine. Somtimes it decides to cut out randomly at 4,000 rpm while i'm getting on it. Sometimes if i baby it it'll go 10 miles or so before it starts. Suspecting an electrical problem i went threw the wireing today and found nothing wrong. When you turn on the head lights the dash lights flicker a bit at idle but it still runs. I was told to check the pcv valve i think its called but i don't see one on it just a hose running from the valve cover to the throttle body. This appears to serve the same function as one but i'm pretty sure it shouldn't have oil in it correct? It doesn't have enough to flow out but it does have some in it. Could that be the problem? It has a dead miss in it and runs very rough. I'm not sure if it's a miss as in ignition miss or it's just trying to die altogether. I've had it put on a dianostics computer and it found everything to be in good shape. I'm totally stumped here and so is just about everyone i know. Any ideas? Not sure if this matters but the exhaust smells really strong. May just be the cold weather and it has been sitting. I thought a car with a cat shouldn't smell as bad.

 

no one has any ideas huh?

 

Since your lights are flickering, it may be a good idea to start by looking at your electrical system first.

Start by removing the connections at the battery, the 2 terminals on the passenger fender, the ground strap near the ICM at both ends, the ground terminal above the starter and the one up front by the radiator. Clean both the terminal and point it mounts to and re tighten.

The next thing you want to look for with regard to "smelling the exhaust" is to check for a dead cylinder. And check your oil if you haven't done so for the smell of fuel.

 

Well i've been trying to diagnose this for a while and i've had it looked at by a few mechanics and they have told me that it is in fact fireing on all cylinders. I've checked everything in the ignition except the coil packs i beleive they are called. I've checked the terminals and all the other easy ones to get to but i guess i should check the one by the starter also. Could it possibley be a bad connection else where in the ignition? I'm not sure if this means anythign but at times it does feel very weak as if it's lost a few cylinders but i attributed this to simply being cold.

 

If you have a 12 volt problem (either ground or supply side), you could have a problem like you speak of. Say the 12 volt supply to the coil where dropping out. Or it was dropping out to the PCM intermittently. Since your lights were flickering, this would be the logical choice to start looking for problems.

If you then look for commonality to the lights and say either the PCM or the ignition system, you limit the choices of inspection down even further. For example, the same fusible link that connects the PCM battery fuse to the battery also connects the courtesy fuse to the battery. If it has a connection problem at either end, it could give you running problems as well as "flickering" lights.

Also, several folks here in the last 4 or 5 months have encountered "cutting out" problems due to a defective ignition switch. The ignition fuse which powers up the coil, is powered through the ignition switch.

 

Well i tried to find the ground you were talking about by the starter but no luck. I do know that the car is rusty as hell from being in michigan most of it's life. I'm thinking you are right though but i'll have to wait till i can take it to a better garage then my little shack out back so i can get it up in the air and look at everything underneath. Thanks