High Idle Problems

[Redlight43]

I have a 99 XLT with a 4.0, when the truck is cold it idles fine. When it is warmed up the truck idles at about 1700 rpm's. Does anyone know what could be causing this? Thanx in advance for your input.

 

[aldive]

Have you checked the IAC?

 

[Wrench]

OHV or SOHC engine?

 

[Redlight43]

It is a SOHC

 

[Cobraguy]

vacuum leak? Throttle body hanging up when warm? Throttle body bushings bad? Just some ideas...

 

[Redlight43]

Thanx all, I will be doing some checking in the morning.

 

[dougb1]

dougb1

I have a 2001 Ford explorer XLT. My explorer does the same thing. I took it this morning to the Ford place and My problem was the Thermostat and the IAC motor. My transmission was jerking in low gear. They told me that it would run fine cold but when temp rises above 210 degrees it causes the tranny to jerk and the rpms to rise. I had already changed the IAC in the parking lot of AutoZone and it did not fix the problem, but the car temp probably was above the 210 limit and I did not give that any thought.