I have a 94 z28, It runs great, its all stock, but sometimes it'll start and drive for an hour, but sometimes it won't start or will start and run great then just completely just shut down after about 4 minutes while i'm driving. We thought it might be the igintion module or coil pack, so we changed both. it seemed to run fine for about 2 days, but now its acting up again, I don't really don't know what to do from here, any body got any ideas?

p.s.(I don't think its the fuel pump, but i'm sure i could be wrong)

thanks!

 

i had one doing this/ first you gotta chk the fuel pressure. about 45psi/ if its ok and you have ignition. and an injector pusle check it with a vac gauge for an exhaust restriction/ I had one that ran great cold/open loop/ but soon as the 02 sensors started giving feed back to the ecm. it would about shut the injectors off because the cat was restricted/ tool a while to find that one

 

Check your harness to the distributor. Sometimes heat cracks form on the connector cavity and where the harness plugs in to the distributor itself. I've had this happen twice and it got me both times. Hope this helps.

 

I was leaning more towards the distributor, but will it run fine and then shut off with a bad distributor?

 

The OptiSpark distributor could cause that problem, if the optical cam position sensor module was overheating, or breaking down due to high heat. That problem would set trouble codes, which don't turn on the SES light. Have you had the PCM scanned for codes after it shuts down?

 

well we just had a temp sensor put on, will it just shut off when it gets to hot?

 

^The gauge was reading wrong

 

The coolant temp sensor for the guage has nothing to do with how the engine runs. The sensor in the head is only for the guage. The PCM reads a sensor in the water pump housing. There is nothing in the PCM that would shut the engine off because it was "hot".

 

SES light?

sounds like what my optis did to me

 

yeah i didn't think that would shut it off.

But no SES light on.

 

pull the codes im sure you'll find the high res pulse error argggg!

 

I think we found the problem, it was the coil, got a bad one from autozone, doesn't that suck.

 

built to last
dura last

 

nevermind!!!! computer said it was the coil, but it shut off 3 times on the way home today, now put on a new brain box, and it still died a couple times! so this thread is still open for ideas. I'm clueless, and this sucks!

 

sounds like were having the same problem. could it just be the wiring harness?