Im currently running a 92-93 LO5 from SDPC2000.com i have the motor partially broken in (about 375 miles and over 2 hrs of unloaded running @ idle total) The check engine light has been coming on after like 10-15 mins of driving, with no change in performance or sound... then i got my new custom chip from TBIchips.com and it works perfectly, no check engine light, no nothing... until.... i rev the engine up a little to accelerate after it warms up after like 5 mins.... then i get an awful sound coming from the engine every time i rev it.. and after the light comes on my throttle response is lacking a lot... im going to check the code tomorrow with the paperclip, light flash method... any ideas though???

one more minor thing... when I drive the car normally without breaking 3500rpm, it doesnt heat up over 200 w/ the 195 thermostat in it... but if i stop @ a stop lite or in a drive thru or something like that... it heats up BADLY... the fan comes on @ around 160-170... i really dunno whats up there.. maybe just new engine blues, or should i get the z28 dual fan setup?? larger radiator???

Yes, it sounds like something is off with the timing, either with the initial timing or the timing in the chip, and the comuter is retarding the timing all the way and going into limp home mode.

timing... hmm.. i really hope that can be fixed on the chip... if not, i gotta get my car re-timed professionally, cuz I dunno how to do it ;-) any ideas of why its heating up... BTW its a 195 therm in my car right now... (160 going in tomorrow, hopefully that will fix the problem)

does the really aweful sound sound like marbles in the heads? sounds like you might have some really bad spark knock

heat could also be a major factor in spark knock if your running timing on the ragged edge.. when you say it heats up "badly" what does that mean? how how are we talkin here?

only once it got past the redline on the temp gauge... but on average i run around 220 in the city... and its irritating.. and the engine timing is set to stock