i was parking my dads truck in the garage and whilein reverse the truck died out. i put it in park and started it again. it started up fine but runs a little rough and but not rough enough tokick on the check engine light. there was a few things done to the truck before the warranty expired and they were cylinder heads, fuel pump and atune up. but that was when the truck had 64.000 miles or so and now the truck has 112,000 miles. i already know that there is spark so its not the crank position sensor right? orso i think not but what else could it be?i'm opened to suggestions here.

 

Try replaceing the IAC valve or Idle Air Control Valve. It's on the back of the thottle body and held in with T25 Torx head bolts I think.

Mine was doing that. It would start up fine and pull out but I could hit the brakes and die, sometimes backing up. Also didn't want to idle cold, it would idle rough or die.
A sticking IAC will cause it. Mine turned out to be a peice of an old breather gasket was holding the IAC open.
Didn't know till after I put the new IAC on and had the same problem, I decided to clean the carbon from where it goes on with some carb cleaner. As soon as I hit it I saw the gasket come out.
I did mine on the truck, it's not hard to remove the whole TB and makes it much easier to change the IAC plus you can clean the TB while it's off.