Hello everyone,

I have an 2001 F150 supercrew with the 4.6L. It runs and drive's fine but when I turn the A/C on and just parked or at a stop light the idle just up and down. It just started the other day. Its fine whem i'm driving but as soon as i stop it goes from 800 RPM's to about 1500 RPM's. IF anyone can help i'll try anything. Thanks

 

You have either a vacuum leak or a sticky IAC valve.

If it's a vacuum leak, your CEL will come on before too long.

Steve

 

When I had the same problem, I checked for vacuum leaks first. I ended up changing my IAC valve which helped (You can also clean these but results vary greatly). The last step was cleaning my MAF sensor - and voila! Problem solved and (bonus) I actually increased my gas mileage when I cleaned the MAF. I would clean your MAF and IAC, as well as check for vacuum leaks first before spending $70 on a new IAC valve.

 

How do i clean them also where are they located? Thanks

 

Sorry for not getting back with you sooner.

Your best bet would be to do separate searches in this forum and the Expedition forum for the key words here - IAC, MAF, idle, etc. There are so many different threads on this subject that you will without a doubt find the answers you need.