I don't know anything about how the engine controls idle. I don't have a tach, but my idle is wayyyy too high. It must be at least 3000 rpms. What should I look at first?

 

throttle plate could be open slightly. i've never had to adjust idle, but i've read about it before. search should turn something up, i think it's just a screw on the iacv but you have to do some other stuff first.

 

throttle plate isn't open, I checked it when I put it in, and when I just put my intake on. This motor just got swapped in. Is there anything that would just stop working after sitting for a long time?

 

Codes 20, and 41 for CEL