2004 Mitsubishi Galant V6 P0300 Random Multiple Misfire - Diagnosis and Repair Steps

Model: 2004 Mitsu Galant Fault Code: P0300 Posted: 2012-04-29 09:55

I'm really puzzled about this ongoing issue. Two months ago, my OBD system detected a P0301 misfire in cylinder #1. I replaced the ignition coil for cylinder #1 and also performed a full replacement of all spark plugs and the intake gasket. Last week, the Check Engine Light returned, and the engine was running roughly. A new OBD scan revealed a P0305 misfire in cylinder #5. I then replaced the ignition coil for cylinder #5. However, during a mechanical inspection, oil was found inside the spark plug tubes. As a result, I replaced the valve cover gasket. Despite these repairs, the engine continues to run roughly, the Check Engine Light remains on, and the OBD system now shows a P0300 code indicating random/multiple misfires. What should I do next? Any insights or troubleshooting steps for this 2004 Mitsubishi Galant V6 with persistent P0300 issues?