The 2022 GMC Sierra 1500 offers the 4.3-liter V6, 2.7-liter turbo-four, 5.3-liter V8, and 6.2-liter V8 engines. For the V6 and V8 configurations, P0305 indicates a misfire at cylinder 5, which is a legitimate cylinder position. The 2.7L turbo-four would make P0305 an anomalous code.
P0305 Code Analysis by Engine
For V6 and V8 equipped Sierras, P0305 is a valid code requiring diagnosis. Cylinder 5 is on the driver's side bank. The V8 engines with Dynamic Fuel Management (DFM) have additional considerations as cylinder 5 can be deactivated during light-load operation.
DFM Lifter Concerns
The 5.3L and 6.2L V8s feature DFM cylinder deactivation that can shut down individual cylinders including cylinder 5. The switching lifters used in this system have been subject to failures causing misfires. Lifter noise often accompanies misfire symptoms.
Standard Misfire Diagnosis
Beyond DFM concerns, standard misfire causes apply: worn spark plugs (especially if approaching 100,000-mile interval), failing ignition coils, fuel injector issues, intake manifold gasket leaks, or on direct injection engines, carbon buildup on intake valves.
4.3L V6 Specific Notes
The 4.3L V6 doesn't feature cylinder deactivation, simplifying diagnosis. Cylinder 5 misfires on this engine typically relate to ignition, fuel, or mechanical issues rather than AFM/DFM system problems.