Truck just started this problem last week, at cold start up the idle will suge between 1400 and 800 rpm, today the wife said it stalled on her this morning at a friends house on the way to work, started right back up and ran OK. NO CHECK ENGINE LIGHT ON. Any suggestions??????????

 

vacuum lines, throttle positioning sensor, bad fuel maybe?

 

Thanks for the Help, it was the TPS, I re-set it from the directions from another post you replied to "rough idle". it worked, seems to idle fine now.