1993 Camaro Z28

[SwaziZ28]

Hi everyone. I've got myself a Z28 that I've done some work to, and had previous work done to it.

Following are the mods:
TSP longtube headers
Straight pipe no cats
Cold air intake (custom)
Msd venter optispark
Msd superconductors (over the valve covers)
NGK tr55s
Msd ignition
160 degree thermostat
36lb/hr Accel injectors
Lunati cam (I forget the specs)
EGR and AIR delete.
Custom chip done by Sinister performance


My problem with the car right now is I have a high idle. I checked for vacuum leaks and cannot seem to find any, and I don't think it's a vacuum problem. The idle for park/neutral is 850cold and 750hot. Idle for in gear is 750cold and 650hot. The car will get close to proper idle in gear around 750-850 but will never achieve 650. In park/neutral it rarely drops below 1k and usually stays around 1.5k.

Using ALDL and tuner pro the only things I can read are injector bank 1 and 2 errors. Everything seems to be fine though. My butterfly is completely closed and the iac is reading 0 clicks. Tps appears to be reading normal voltage. The car is requesting the lower idle but never achieves it.

Maybe someone here has some insight on what I can do... I'm basically at a loss on where to go.

[Naaman]

Did this problem begin after a particular part was installed or some work was done on the car?

I don't have the LT1, but on my car, when I installed a P&P throttle body, my O-ring for the IAC valve was damaged and it resulted in a high idle that would not resolve. Took me a week to find the cause, but was glad it turned out to be only a $0.15 part. Have you checked the O-ring on the IAC? If it's original, it's certainly old by now!

[SwaziZ28]

Problem occurred after the motor was put back together (cam, New opti, New plugs, etc)

The idle was MUCH higher before the chip. Im probably gonna end up pulling the intake and throttle body and check over that little crap. I didn't disturb the iac or tps, but I guess it wouldn't hurt to check.

[Naaman]

Good luck! Post your results.