i have figured from what i have read on here that it is most likely the icp sensor, but today i was driving home and stopped at a light by my house and the tuck was idling really bad and rough like a gasser was misfiring and its never done that before. so i shut the truck off and turned it back on and the same thing. so i coasted in neutral down my road and it sounded like it idled fine while coasting, but once i got to a stop it was rough again. i also looked under the drivers side fender well and saw some kind of gunky build up on what i think is the injector harness right above the header. it also made a squealing noise under acceleration. does anyone have any idea what this could be? here is a pic of the egr.