The 2021 GMC Yukon launched the current generation of GM's full-size SUV, featuring powerful V8 engines with advanced Dynamic Fuel Management. When your Yukon displays P0304 indicating a cylinder 4 misfire, understanding the DFM system helps guide effective diagnosis.
Understanding P0304 in the Yukon
The Yukon's 5.3L and 6.2L V8 engines feature Dynamic Fuel Management, which can deactivate any cylinder combination for optimal fuel efficiency. Cylinder 4 is located on the right (passenger) bank of the V8. The powertrain control module monitors each cylinder's contribution through crankshaft position analysis.
DFM System Factors
Dynamic Fuel Management uses advanced lifters that control individual cylinder deactivation. Issues with these lifters can cause misfires, particularly during transitions between active cylinder configurations. The DFM system requires proper oil level and quality for correct operation.
Diagnostic Steps
Access the cylinder 4 ignition coil on the right bank. Inspect spark plug and ignition coil condition. Monitor when misfires occur—during steady highway cruising suggests DFM involvement. Check oil level and verify Dexos1-approved oil is being used.
Resolution Strategy
Replace spark plugs with AC Delco specifications if worn. Test ignition coil output. If DFM lifter issues are suspected, inspection requires valve cover removal. Ensure oil changes use correct specification for DFM operation.