After reading several threads that mentioned TPS (throttle position sensor) problems, i decided to just replace mine and see what, if anything, happened. Well, it pretty much fixed every complaint i've had about my truck including....
1. my truck was a pig. no power, no low rpm torque. couldn't get out of its own way.
2. wouldn't hold overdrive. always downshifting.
3. wouldn't pull a hill. acted like it was trying to climb mount everest. slowed down more and more and more until you stomped the gas to make it go.
4. when you wanted a liitle more power and you mashed the gas a little - nothing happened. you mashed it some more, still nothing happened. you mashed it a little more, and it downshifted and took off like you wanted to race.
5. it wouldn't hold speed on cruise control. always slowing down and then downshifting and trying to catch up.
etc etc.

so anyway, i put on a new one for $40 from local parts store. it fixed all these problems and its like driving a new truck. just a by the way, i got one from autozone that was a Wells brand and it was expensive ($68) and the electrical connector was slightly misshaped at the top and my plug wouldn't slide on. it was the only one they had so i wasn't able to try another one. so i don't know if it was just a fluke or not. The $40 one fit perfect.

so then i wondered why this fixed so many problems and came up with all this.
trucks don't have carburetors anymore so the fuel control is from the computer, telling the injectors what to do. trucks don't have centrifigal nor vacuum timing advance anymore (i don't think) , so the timing control is from the computer. The TPS is what tells the computer what you are doing with the gas pedal.

hope this helps someone....

 

Nothing like a $40 fix to a whole pile of little annoyances! If your TPS was giving you that much trouble, you might try replacing your IAC as well, or givng it a good cleaning.