I have noticed when the engine is cold, my truck tends to surge when under very light throttle. It only does this when cold. It doesn't feel like a slipping tranny, nor like a plug misfiring, but rather like the throttle is being feathered on and off.

Any of you have this issue? What is it? Fuel pump issues?

 

Frequently, the problem is the Throttle Positioning Sensor (TPS). Try replacing that first.