CUSTOMER CONCERN The engine misfires, lacks power, and may stall. The condition can occur with or without cylinder-misfire or lean DTCs. CAUSE The confirmed repair identified failed ignition coils and worn spark plugs as the source of the misfire and drivability symptoms. CORRECTION Remove and replace the failed ignition coils and spark plugs, clear any stored misfire DTCs, and road test to verify normal power and idle quality.

CUSTOMER CONCERN The engine misfires and stores DTC P0300, with the misfire isolated to one cylinder. CAUSE Swapping the spark plug and wire moved the misfire to another cylinder, confirming failed ignition secondary components. CORRECTION Remove and replace the spark plugs and spark-plug wires, clear DTC P0300, and verify the misfire is eliminated.

CUSTOMER CONCERN The engine runs very poorly after air-filter service, pings under load, remains in open loop, and stores lean and misfire DTCs. CAUSE Inspection confirmed debris contamination on the mass-airflow sensor element, causing incorrect airflow measurement and the lean misfire. CORRECTION Clean the mass-airflow sensor element and air-filter housing, clear the DTCs, and verify closed-loop operation and normal engine performance.

CUSTOMER CONCERN The engine runs rough with a timing-chain rattle and stores DTCs P0011 and P0300. CAUSE Diagnosis confirmed a worn timing chain as the source of the camshaft-timing fault, misfire, and rattle. CORRECTION Remove and replace the timing chain, clear DTCs, and verify smooth engine operation without timing-chain noise.

CUSTOMER CONCERN Engine misfires on cylinder 6 and compression testing shows no compression on that cylinder. CAUSE Inspection confirmed a failed valve roller lifter on cylinder 6. CORRECTION Remove and replace the failed valve roller lifter.

CUSTOMER CONCERN Engine misfires under acceleration with DTCs P0302 and P0304. CAUSE Circuit testing confirmed a fault in the affected fuel-injector wiring. CORRECTION Repair the failed fuel-injector circuit wiring.