Got a ZZ4 crate engine installed last year in a 1989 camaro. GM dealership build and install. It has 30lb injectors, and a Fast chip made to run it. everything else is stock except the exhaust. It has hooker headers, 3inch y pipe and an 3.5" American Thunder Exhaust system. It has 3:42 gears and a Retro fit T56 trans. The car runs low 13's. since last year I put on an adjustable fuel pressure regulator. Just wondering what fuel pressure psi is recommended? Anyone have a ZZ4 swap with TPI would love some input on this matter. Also Bought a stock Throttle Body bored to 52mm. I put a new IAC sensor on it and dialed the TPS to .59 at Idle. Since doing this the car idles like crap about 500 rpm cold when it warms up its running 1000rpm. It also surges at idle. What can I do to fix this problem? Please help!

 

Did you do an iac reset after adjusting the tps and changing the iac sensor? If not I would start there. Fuel pressure at the rails is usually between 45-50psi for tpi systems.