when I pull up to a stoplight or in the driveway, sometimes the truck will idle up to 1000-1100 rpms and has a slight miss. I can let out on the clutch a little to load the motor and the rpms will settle back to 750 and the miss will go away. Also, if I depress the clutch and let the rpms settle to an idle, I can tap the accelerator pedal and the rpms will climb to 1000 or higher and stay there then I have to go through the ritual again. Anyone have any ideas as to what is causing this?

 

The only time I've had mine go in to high idle when in was in Park for several minutes and outside temp was around 30 degrees. As for the miss if its cold enough to kick in high idle then is also may be the grid heater kicking in and thus making you think its missing.