I'm a little behind on this one but if you haven't fixed it yet, here are some things. First, it is a 4.3 litre engine, probably typo but you never know. This truck has a tps(throttle position sensor), and pedal position sensor(pedal position sensor). Either can cause this problem. Also the throttle body can be damaged. There were several year models when the throttle body had issues. As far as I know, a regular scanner won't hook up to this system. Hope that helps.