i have a 92 chevy truck with the 91 z28 motor, just had prom work done by jimsperformace, runs rich, also when i first try to start the truck it will fire then die ever time, i have to keep my foot on it to get it to start and run..."also dark smoke when i rev it at start" after about 20-30 secs it will then stay running " vary rough idle" do u have any ideas why? also after it gets to running temp it seems to want to hunt for an idle fluctuates about 300 rpm. can anyone help?
after reading some of the tech pages, i found that it might be that my prom and my thermostat dont match, could this be part of the reason?
things that have been done to the motor---
motor has been bord .40, xr264hr-10 comp cam, 1.52 roller tip rockers comp cams, 24lbs, AFPR, bbk 52mm, no air pump, no egr hook ups, hope this helps!

 

also im thinking that it runs to cold and is not goin into close loop...how do i tell if it is in closed or open? could i have bad sensors?

 

Could be a bad tune in the chip or could be mechanical. Hard to say, I am running into the same problem and it has lead me to burning my own chips. I also suspect an injector problem as well. Go over the mechanical stuff first and then call the chip tuner back. They should try different burns for you without charge since the one you bought doesn't work.

 

I once accidently left the vacuum hose off to the MAP sensor., and it ran exactly as you describe. Check that as one possibility. Ed www.edgesz28.com