Questions about cruise control and an idler in a 2005 Ford Sport Trac?

[BrandonC]

I am about to head off to college in a week and recently just purchased a 2005 Ford Sport Trac. It has no major mechanical problems except for the Cruise Control does not engage and when I start the engine, the engine sounds like one from a 60's era muscle car. It shakes a bit and sounds like a big block V8. If I apply a little gas then it stops that and returns to normal. My dad said it was due to the idler being cold or something like that. I plan on taking it to the Ford Dealership here next week and would like to know from someone on here what the problem could be with the Cruise and the Idler. Thanks