I have an 86 Z28 with a 75 four bolt main 350. I just recently did a TPI sawp. I used a painless wiring harnes. The car want's to search for an idle 500-1500 rpm.

75 350 .040
Flat Top Pistons
Mellings Bumpstick
LSA: 114
Duration: 224 Intake & Exaust
Lift: .450 Intake and .461 Exaust
New Accel 24lbs Injectors
461 Doudle Hump Heads
10:1 Compression Ratio
New Knock Sensor
New TPS set at .54 V
New IAC
New distributor
New Coil
New AFPR
New O2 Sensor
New MAT
New CTS
New Coolant Temp
New Egr and Soliniod
No Trouble codes
New MAF
ALL New Relays

Any one have any ideas in why it would search for an idle speed ?

 

I just adjusted the idle speed and it got the idle to smooth out but it idles at 1100 rpm. One other thing I my using a motorvation strip chip

 

Did you try resetting the IAC. I believe every time it is removed from the throttle body it needs to be reset. Just search IAC on this site there is a good post on how to reset and adjust the idle.

 

Yes i already did that

 

Do you know what the target idle RPM is programmed at? Your custom PROM may have a relatively high target idle for a long duration cam, plus extra IAC steps, in addition to the added IAC for a lower CTS reading. Is the coolant sensor working?

 

I think you'll need a little custom tweaking in the prom, you have more of a carb cam (low lift, long duration) as opposed to a tpi grind which favors higher lift and shorter duration.

 

I readjusted the IAC and the TPS and no the it idles fairy smooth at 1100 rpm in park. Tonight I'm going to mess around the the fuel pressure, to see if i can improve the idle even more.