I have 2000 f-150 125,000 miles. Engine idles very rough when the ambient temp is below 20 degrees. I have replaced the idle air control, both up stream 0-2 censors, 2 vac lines that come off left side of throttle body, cleaned air temp censor in air intake. when I say cleaned, i sprayed with electronic cleaner, that did help my fuel mileage. check eng light is back on, have not had a chance to see what code is now. PLEASE respond to chuck3902@insightbb.com

 

air temp sensors are very fragile. list the code you get would be helpful.

 

I'd clean the MAF sensor, with the spray cleaner made for that. It's probably still working just fine, but road grime build up can cause your problem ( and not always trip a trouble code).

Dave

 

5.4 or 4.6L? Start with the trouble code as well.

 

Don't chase it until you read the code. I chased a bad idle... lack of power when cold on the son's 2000 Sunfire with all kinds of things. It had been tossing a cat. code for a year....would come and go. Even though I know better, I ignored that and spent 100's on sensor's and my time. A friend who is a mechanic said pull the ex. pipe at the manifold and see how it runs..... Ran perfect...story short....plugged converter. Lesson learned....start with the basics.