1999 5.4 4x4 runs rough between 1200 & 1500 rpm
 

Truck runs great until I am cruising at 1200 to 1500 rpm's. Acts like it has a high performance cam (doesn't want to accelerate smoothly like the rest of the power band). Kind of acts like its starving for fuel....or air. Not sure which! Check engine light is NOT lit. Thanks for any input.

get any trouble codes pulled a trouble code will be set before a MIL will usually. any recent repair history tune up. is this the original drive train power train to the truck. how is the idle temperature and gauges.