94 f-250 going down road started feeling small vibration ,looking out mirrors to check tires saw puffs of black smoke made way to exit and parked on ramp. by this time a wall of white fuel smelling smoke was coming from exhaust and every joint in exhaust syetem,hear small pecking coming from top left rear of engine.had truck towed home. 98000 miles ,nocheck engine light. probally has some kind of chip according to input from other ps owners in area. someone before me put 6" exhaust and boost gage on. any help with opinions and i will turn wrenches in the morning. thanks ebp is ok,swapped idm with good one , no help