99 f-250 powerstroke revs high

when i start my truck it idles good ,then after about 2 minates it goes up to 1000 rpms untill i touch the peddle then it goes back to normal then after a few minates it goes back up ,anyone got a clue
thanks
bob

At operating temp.,disconnect the battery for 5 mins. Restart at operating temp, w/ you foot on the accelerator, have someone disconnect the IAC. as the Idle drops out, maintain it at 650 RPM with the accelerator for 2 mins. then turn off the engine for 1 minute & plug the IAC back in. restart and let Idle for two mins. shut off for 1 minute. Restart, put foot on brake & let Idle for two minutes. shut off for 1 min. What do you have for an Idle now? This assumes no active error codes or Vac leaks when performed.

this a powerstroke 1999 ,i dont think it has an iac

had a crank sensor put it in recently?

no ,no work ever on it

Sounds like Exhaust back pressure sensor on the front of the motor.

would that be called something else

would that be called something else

EBP sensor, Exhaust back pressure ...