Have an Evo IX SE, basic bolt on's, tuned by Chad at CBRD last Sept. Recently car has started to hesitate while cruising at 60MPH, 4th gear, 4000rpm after cruising for about 8 miles. Seems fine idling and accelerating. I don't have a lap top to log, but my wideband is dropping from 14.50-14.28 range down to like 14.20- 13.80 when the hesitation starts, never dropped below 14.20 before when cruising. Also getting a little more exhaust backfire/pop when letting off the throttle. Car accelerates fine, changed plugs 6000mi ago, checked them they looked fine, light brown, and I rechecked the gapping. Could this be fuel pump, injectors or sensor? Am I statting to run richer? Can a car go out of tune?