The 2019 Cadillac Escalade triggering P0300 may have misfires related to the Active Fuel Management (AFM) cylinder deactivation system. The 6.2L V8 in this full-size SUV deactivates cylinders for fuel economy, but AFM issues can cause misfire patterns.
Understanding AFM
Active Fuel Management deactivates half the cylinders during light-load cruising to save fuel. Special lifters collapse to disable valve operation in cylinders 1, 4, 6, and 7. The system switches seamlessly between V4 and V8 operation.
AFM-Related Misfires
AFM lifter failures are a known issue on GM V8 engines. Lifter collapse or sticking can cause misfires that appear random (P0300) or affect specific AFM cylinders. The pattern may correlate with cylinders equipped with AFM lifters.
Symptoms of AFM Problems
Rough idle or misfires, particularly affecting cylinders 1, 4, 6, or 7. Ticking or tapping noises from the engine. Check engine light with misfire codes. Reduced power or hesitation during cylinder transitions.
Lifter Failure Diagnosis
Compare misfire counts across cylinders. AFM cylinders failing more than others suggest lifter issues. Listen for valve train noise. Collapsed lifters may produce distinct ticking.
Repair Options
Some owners disable AFM through tuning to prevent future lifter issues. Lifter replacement requires significant engine work. DOD (Displacement on Demand) delete kits replace AFM lifters with standard lifters.
Repair Costs
AFM lifter replacement runs $2,500-4,500 due to labor. DOD delete with standard lifters and cam costs $3,500-5,500. AFM disable tune alone is $300-600 but doesn't fix existing damage.