hello,
I have a 2001 f150 that just started this won't idle issue. I have been reading and it looks like maybe the idle air control is going bad? It will run fine if you keep on the gas and it did idle once it was warmed up. I'm letting it cool down now to see if it happens again cold. But where is the idle air control located at? Ran it into work fine and when I got ready to leave it wouldn't idle so I limped it home keeping the rpms up and when I got here it was idling again(about a 15 mile trip). It hasn't tripped any codes in the computer yet. any help appreciated. thanks.

 

If it idles while you give it gas, I'd say the IAC is bad. The IAC is attached to the throttle body and can be changed in less than 10 min. Personally, I like the Ford part better than the parts store, but its about 2x the cost (but, seems to last more than 2x longer).

 

pretty sure it is the IAC but i'm not sure where its at on the 5.4, I think I see it conveniently located up under the firewall on the back side of the engine!! looks like a real pain to get out? sound right 5.4 guys? about all I can see is the top of it opposite the plug side I see the bolts?

 

Check this link for a picture

https://www.ford-trucks.com/forums/1...-98-exped.html

 

Thank you Joe that was where I was thinking it was.

 

On my 4.6 the IAC is pretty much right on top, I didn't realize the 5.4 stuck it in back of the throttle body. Let us know how it turns out.