I have a question about idles. I have done extensive research on this and havent found a solution yet.

97 F150 5.4L 4x4 145,000 Miles

The truck seems to have a rough idle, it has no problems running, but not a smooth idle. I may just be picky, but to me it is downright annoying.

I replaced all spark plugs, new fuel filter, new air filter, checked all coils, and checked vacuum of PCV valve. ALL ARE GOOD NOW!!

I run premium fuel and have ran injector cleaners through twice. I forget the brands, but both were "quality" brands (at least from the price). I got fuel from different gas stations to rule out the "bad gas" theory.

Can anyone offer me some help on my idle woes?!

 

Does anyone have any ideas?

 

Is your engine light ever come on?
The only thing I can think of is the throttle position sensor

 

Might be a vacuum leak or dirty IAC valve. Also check your PCV valve hose all the way back to the throttle elbow to make sure its not cracked or leaking.

 

No Check engine light...

I will check the PCV hose.

How dd you clean the IAC?

Thanks

 

Its located on the passenger's side way back behind the throttle body elbow and mounted with 2 bolts and has a electrical connector. Remove the valve and clean off the carbon with a throttle body cleaner and Q-tips. It's a good idea to replace the mounting gasket when reinstalling. If it's really got bad carbon build-up, the valve may have to be replaced.

 

Thanks!!