I have a 97 F150 4.6 motor went bad the rings went out I put a 2000 motor in Reno right now I’ve got a high idle it won’t take no acceleration that’s after I replaced the mass airflow which is true coat on and a whole bunch of other stuff just throwing parts at it at this point throttle position sensor idle air control and now it’s just it idles high dies under load now I went to the 2000 motor I had to put my coil packs of the 97 on it because it has a coil free cylinder other than that I don’t think I think everything else is the same any any suggestions

 

I would check for vacuum leaks.

 

You sure the ECU is compatible? Are the parts you swapping out for a 2000 motor or a 1997? Did you ever check for those vacuum leaks? Weird that your problem seems to be changing as you swap out parts.