tap ur iac and tps motor on the throttle body when it acts up liek that and see what happens, when u hit either or and it goes back to normal it is one of those motors, most likely either one of those is ur problem

 

If the IAC has stuck once, It will do it again. I would replace the IAC with a new one. Clean the IAC opening in the throttle body and when you put the new one on, you will need to reset the ECM to accept the new IAC.

You will need to disconnect the battery and turn the key to the start position and hold it for at least 15 seconds and repeat it at least two more times, this will reset the ECM and clear any codes that you may have.

If you do not reset the ECM you will have the a very dangerous problem with a runaway truck as when you will touch the throttle it will rev up high as indicated with your original problem.

If you still then have a problem with the idle being unstable in a smaller rpm range and occasionaly kicking out the cruise control then you will need to replace the TPS and it will allow the idle to be a lot more stable.

 

you dont have to unplug the battery.. or reset the ecm. it just has to learn its idle. so u put the new one in and turn the key to on, engine off for about 5 seconds then start it(in park) and i will at 2000 for about 30 seconds and drop down, dont hit the gas, just let it do its thing until idle is normal.

 

so before i replace anything in the truck (with money i dont have), say i clean out the throttle body and flush the radiator (the antifreeze looks like rust soup). could that possibly do anything?