Today was the first cold morning of the winter, consequently the first cold morning that I've driven my truck. Overhead said 32 degrees out, which dropped to 30 by the time I got to school. At any rate, the windows were all frosted up so I started the truck and let it idle for a few minutes while I cleaned off the windows. After about a minute, I heard the idle go up. Checked the tach, sure enough it had raised to 1000 rpms from the standard 650/750 (I forget). When I was done scraping and drove off at the second stoplight it had dropped back down to normal. When I got to school, I parked it and let it idle while I got out my extension cord to plug in the block heater (since I spend too much time here for my own good). Sure enough, after another minute or so the idle jumped up to 1000 rpms again.

I thought the 6-speed trucks weren't supposed to have a fast idle feature, and that on the automatics it was engaged using the cruise control? I've never seen my truck do this before, but it seemed systematic and built-in to the truck's computer. Has anyone else experienced this on their trucks, and is there any documentation that says this is what's supposed to happen? Are there gremlins living in my truck that just hit the go pedal a little when I'm not looking?

My truck does the same thing. anytime below 40 or so. I'm pretty sure it's normal

Seems like I read in the manual that this should happen at 32 degrees and below as read by the overhead display. Mine seems to follow this trend, but I read on the TDR that some trucks don't do this when they should and others that do it in 70 degree weather.

I was glancing through the manual last night. It also has the automatic high idle when the engine water temps get too high.

Mine does this also.

my 6 speed does it also,, did it this morning at around 30 degrees

mine does it all the time. It never did it until I moved to alaska. If its really cold it will start idleing faster if it sits more than a minute at idle