MIL, any combination of Accelerator Pedal Position Sensor (APPS or PPS) fault codes such as P2121, P2122, P2123, P2127, P2128. The engine may intermittently loose throttle response.;There has been recent repairs or modifications to the truck. The ECM was recently replaced or The ECM was recently re-programmed with an aftermarket 'downloader' device. Verify the ECM is programmed with the correct calibration (displayed ECM part number). If the ECM is not calibrated to the correct part number, the ECM will have to be replaced and flashed with the correct calibration (ECM part number). Hope this helps you. I'll see if i can get the diagrams. Also Inspect the engine to body ground strap located between the left rear of the cylinder head and the left side of the bulk head for wire harness contact.