I've searched for answers to this problem and have done everything that has been discussed as fixing the idle problem and still nothing.

I bought the car with a knocking engine, put a used engine in and now it idles at 3000 rpm and slowly drops every time i start the car. I've had it scanned and got a tps and secondary o2 sensor codes so i swapped the tps with the old engines one and still nothing. swapped the iac, map, replaced vac line on map, and checked intake for loose bolts and did the wd40 test with no change in how the car runs. I also swapped the complete throttle body and again no change. Could the injectors cause this? I'm going to swap the complete fuel rail from the original engine and see what that does since the old engine ran fine other than knocking. And how long do i need to leave the battery unhooked to reset the ecm after changing sensors around? One post i read said the problem stayed even after a new iac was installed until the ecm was reset.

thanks in advance for any help or ideas

have had a mechanic gas it?

check o rings on injectors?
check wires going to TPS


just some thoughts



8 psi with m62 and IAT under 100

Had the same problem. never did find out what it was. I ended up pulling the iac out adjusting it manually and leaving it unplugged. should idle fine once you get it adjusted in the right spot.