Cold engine truck starts just great and idles at higher RPM until engine is warm. Then it idles down. It use to idle around 750-800 but now in gear it idles around 500 or less. I noticed as I come to a stop it gets really low almost like it is going to cut off but then slowly recovers back to 500. The engine does not hesitate in response. I cleaned my air intake sensor, KN air filter has been cleaned.

Any help would be greatly appreciated.

 

Next thing to clean is the throttle body.

 

glc I have never taken one of these off before. Is it best to clean it off the intake or can you clean it in place running. I was told that there is a throttle body cleaner and to use it only. Any helpful tips would be greatly appreciated.

 

It needs to be cleaned on the bench with throttle body cleaner.

https://www.f150online.com/forums/ar...ttle-body.html

I think that's for the old mechanical throttle, but the basic procedure should be the same, you don't have a throttle cable to disconnect, just electrical stuff.

 

Well just got finished cleaning the TB with TB cleaner and also cleaned the MAF sensor with MAF sensor cleaner. The TB had a lot of hard carbon buildup above and below the flapper valve. After cleaning I could see more clearance between the flapper and the body wall. Installed new o-ring TB to Intake and put everything back together. I also removed my KN air filter due to having to oil it after cleaning. Read many issues on using this type filter. I installed a new stock air filter for now. I will probably get an AEM brute dry filter system later.

Now when I come to a stop in gear the engine never gets below 500 and recovers immediately. Fantastic. I did test it on quick stops with AC on and off. PASSED all tests. Thanks for all the help.