99 F250 (5-98) high idle/cold idle while driving

[Travis7.3]

i have a eairly 99 7.3 and when it gets cold out i start the truck and let it idle a few minutes later it goes into high or cold idle. then you hit the brake pedal or gas pedal it goes away like it should but this year its been coming on and off as im driving down the road. when it comes on if im going down the road i can take my foot of the pedal and it turns off and then a minute or sooner it comes back on. i didnt not have this problem last year at all ..i live in northern Ny so our winters get pretty cold but it was doing it on a few morings were it was only 40-50 degrees.. does anybody know or have had this problem???????? since last year i have put a 4" down pipe on it and have a straight 4" exhaust the down ppipe was the only thing i changed. other then that i have the same "cold air" kit as last year and usally get my fuel from the same places..the egt gauge is normally around 4-600 while driving and i have noticed when it comes on while driving the temp comes up about 50 degrees ..i just want to make sure im not going to burn down the motor or if its some sensor i have to change??? any help would be great ...

[Rhino673]

I am having almost the same problem. When I put the truck in park after about 2 -3 minutes the idle will creep up to over 1000-1200. As soon as i touch the brake or bumo the throttle it goes back to normal.