GMC C1500 engine idles but lacks acceleration and power, experiencing backfiring and knocking issues on GMC C1500

Some GMC C1500 owners report experiencing a lack of acceleration and power while idling, accompanied by backfiring and knocking issues. These problems may stem from low fuel pressure, which should ideally be between 9 - 13 PSI, with a preference for 11 - 13 PSI, as inadequate fuel pressure can hinder performance. Additionally, a malfunctioning Ignition Control Module (ICM) can cause similar symptoms, particularly when the engine warms up, leading to backfiring and reduced power, especially if low-quality parts are used. Compression issues may also contribute to backfiring and power loss, with some owners finding that adding oil to the cylinders can help restore compression levels. Incorrect engine timing is another factor that can lead to knocking and backfiring, highlighting the importance of proper timing adjustments. Furthermore, a loose gas cap may trigger changes in symptoms, indicating potential performance issues. A clogged fuel filter is another concern, as it can impede acceleration and power, making it essential for owners to replace the filter and test fuel pressure. Lastly, performing ECM tests, such as tapping near the knock sensor, can assist in diagnosing knocking issues. Addressing these factors systematically is crucial for resolving the performance problems experienced by GMC C1500 owners.