I have a F150 1994 5.0L with Auto trans. The truck sometimes runs fine then it has the check engine light on. It Idles hit and shifts rough. I ran the codes and changed my TPS and IAC. It seems to run find when my ldle is down to correct position. If I take if for a ride. It seems good for a while. Then my check engine light will come on again and I believe it is idling high again. I don't get any codes when my idle is correct. If it is idling high I get the TPS code again. I play with the throttle I can get it down again. I am not sure what is going on.. Help>..

 

Did you reset the ECM after installing the new parts?

 

Post the codes.

Robbie