Can anyone give me some idea where to start. my truck seems to get stuck on high idle even after it warm up in cold weather. when driving, i have to throw it in neutral and rev it in order to drop the idle back down.
Thanks!

 

Sounds like your choke is sticking...

 

Since you say "in order to drop the idle back down" I am taking it that it will idle normally at times and stick as you slow down from driving it. It may be as simple as a dirty choke/linkage sticking. Spray the choke and linkage with carb cleaner. It could also be a worn or damaged throttle linkage that is sticking. If you have an automatic transmission, the transmission linkage could be binding. Or if anyone has removed/messed with the air cleaner assembly it may have been put on incorrectly and is binding the throttle linkage.

There are other causes also depending on what has been done, modified or repaired on the vehicle.

 

...or a weak return spring.