OK I have looked and not seem any problems that are like mine. My wifes Jimmy is a 4.3 auto with 103K on it. Intermiently when at a light the engien will bog down to around 300 RPM (not stall usually) the reves up when it recovers to around 1200 RPM causeing the truck to want to lurch. I have changed the plugs, wires, filters, car and rotor. I do get a chech engien light sometiems for O2 sensor I have changed 2 out. Code still comes and goes when it wants.EGR looks good, no blockage. Cam sensor reading is -5 degrees most of the time it does drift to -6 and -4 occasionally. Any help would be good i was thinking cam senor is bad. I does start hard usually on the second time for cranking.