my my truck has a high idle

Duke,

On you particular vehicle there are a number of things that can cause a high idle under the conditions your describing. A few of those things revolve around a number of sensors and/or their related circuits. At this time don't take it upon yourself to buy or replace any sensors. If you do all you're gonna be doing is wasting your time and money by throwing parts at the problem. Right now, do what's being mentioned below and post the results.

Using an "Engine Vacuum Pressure Gauge" rule out one or more engine vacuum leaks.

Thoroughly clean out the "Throttle Body" paying special attention to the "Butterfly" pivot points.

Make sure the accelerator pedal is not being restricted in the car by a mat, rug or anything.

Thoroughly lubricate the accelerator cable using "White Lithium Grease". Comes in a spray can.

Try a few applications of a product called "Seafoam". You can buy Seafoam at any auto parts store. Trying a few applications means at least 4 applications, and be sure to use the Sea-form according to the instructions on the can.

If you're using cheap gas stop using it, and start using a "Top Tier Fuel". Also start filling your fuel tank at the half-way mark, if that already is not being done.

Auto Zone stores read computer error codes for free. Go to any Auto Zone and have a scan for stored computer error codes done. Post any code or codes that are set so we can see them.

Do all the abopve for now and post back the results.