Just got my truck back from Ford and I have had so much problems with it I am not sure if I am just being paranoid, but here it is.

My truck idles around 600ish. But it seems low sounds low and the idle moves up and down slightly. It does not come close to stalling or anything but it sounds like the idle drops and then the computer or something corrects it and brings it back up every few seconds. It is very minor but I just want to make sure everything is perfect before I mod anything.
What could I check to make sure it is correct. The only thing I can think of is maybe they knock the TPS sensor and that has it off a little but not really sure if that is what controls it.
Thanks

 

Tom I would check TPS voltage first.

 

Erratic and fluctuating idle on a normal running Lightning,
usually point to the IAC needing cleaning ???
But with Ford Dealership Mechanic's touching your vehicle,
of course it could be anything

 

gONNA CHECK BOTH this weekend.

 

There's also a kit Ford sells to adjust the IAC if cleaning it does not solve your problems and you pinpointed the IAC as the cause. I don't have the part number on hand, but I believe Tim@REM knows. You may want to give him a buzz to see if he can sell you one or offer you the part number.