This is sort of odd. My car won't idle when cold, but once the car is warmed up and running, she'll idle fine. When building the car recently, we discovered a bad IAC valve, as it would idle at 2000 RPM when warm. Now, with the new valve, it appears to run fine once at operating tempurature. We DID remove the Smog Pump... could this cause issues?

Thanks for any input.

Car Specs: cam 282 intake/282 exhaust Duration at .050 in. cam lift 224 intake/224 exhaust, Gross valve lift: .465 in. intake/.465 in. exhaust, Lobe separation: 114 degrees, Stock L98 Heads, Ultimate TBI mods, TBI Riser, Injector Spacer, Edlebrock Performer TBI Intake, custom midlength headers, custom Y pipe, 3" flowmaster exhaust w/ Cutout, 3.42 Posi Rear end, open element, !Smog Pump, MSD ignition, 180* T-Stat, Stall Converter (not sure what, feels like 1800 or so), Shift Kit.

 

Just removing the smog pump should not cause those kind of issues.

Adding almost 80 cubic inches to engine displacement and probably a hotter cam is the likely cause. The stock programming doesn't stand a chance at runnign that engine correctly. You might want to check with the guys in the ECM programming section of this board. I think they could probably help you a lot more than I could.