I have a 86 TPI unit in my S10. I am using GM stuff and harnesses, etc.. I acnnot get the engine to idle at specs. It always adjusts itself to 1000 using the IAC. I changed computers, proms, etc. (I wired it having the park/neutral circuit to ground like shown from suncoast wiring schematics). The transmission is wired independantly of the ECM (making it think it is a manual trans vehicle). Even usung a third prom (hypertech thermomasterchip) it still does the same thing. I even switched MAF, same results. I get a check engine light on cold mornings but clears up when warm. I am using the recommended 160 thermostat. I checked the codes this morning but again, intermittent. (34, 52, 53) I called hypertech but they said the chip does not control idle - it is built in the computer itself. PLEASE HELP! thanks in advance, sorj.