I had an issue I was tracking down and eventually my truck would not idle for about 2 days if you let your foot off the gas. I searched these boards to get an idea after I pulled the P2106 code and didn't find anyone having a problem with holding idle either, just dying, which I already had. I was able to replace just the throttle position sensor, though you may have to replace the whole throttlebody if that's your problem. The new TPS took care of the issue for me, do some diagnostic work first if you can before shelling out the cash for anything though.
EDIT: ctsv510 was mentioning the actuator itself, this code is related to the entire throttlebody control system. This could include the TPS, the actuator motor itself, the wiring, etc. It's unlikely that the actuator itself is bad, more likely it's the TPS. Check the wiring to all of that first and see if anything is frayed or damaged as a start.
Last edited by Jawsh; 05-16-2012 at 12:11 AM.