UPDATE BELOW! ( here: http://web.camaross.com/forums/showt...32#post3816132 )

I took quite a while to finish the project, but I put some ported heads, ported intake, bret bauer cam, 30# injectors, electric water pump, 1.6rr, !egr and a pcm4less tune.

It ran for about 100 miles the first time I took it out, but I didn't know about poly locks so my rockers came loose and I bent a couple rods. I'm not sure if this had anything to do with my current problem, but I just replace the rods and rockers.

Now the problem is - I can start the car up cold and it runs GREAT. Then after about 5 minutes of running it starts to not want to run at lower RPM. The longer it runs, the less it will run at lower RPM and after 15-20 minutes I have to keep it over 3k to even keep it running.

If I try to restart it after it dies in this condition it takes forever and barely hits slowly and then finally starts running if I pump the gas a while and keep at it.

I replaced the fuel pump (walbro 255lph) and had the whole fuel tank cleaned out - no change. I bought a MSD 6AL and a new coil I'm putting on this weekend, but I don't actually think this will fix it. What else could it be? dreaded opti?

Everything was pretty much original, 1995 Z28 with 107k.

Thanks,
Craig

 

I had the same symptoms - opti-spark harness. Probably not the same reason for you, but something to look into.

 

SES on? Sounds like what happened when my opti went out.

 

Just something else to look at. One of the b-body guys had a problem where afer a few minutes the car wanted to "run out of fuel" turned out the CCP was messed up and vacuum was building in the tank till the pump could no longer overpower it.

 

Ccp?

 

its called loading up my friend

 

Update: I installed the MSD Coil and the MSD 6AL box, and there was no change - it still runs like crap after a few minutes.

However, I got some more info. I pulled most of the plugs, and so far every one of them is black, nasty, and WREAKED of fuel (with less than 200 miles on them). So, at least I know it's loading up across the board and not just one cyl.

Also, I noticed as it started running rough the TracControl light and Brake light started coming on intermittently, and then the Air Bag light came on and were all blinking as it started to run REALLY rough. WEIRD!?

So, does anyone think a capture of the OBD1 data will help diagnose this? Something else to look for? I don't want to invest the time/money in a new opti if that's not it.