2004 VW Passat P0301 and P0302 Misfire Codes - Common Coil Issues
This is my son's car, but I'm posting it under my name. He reported the vehicle wouldn't start and could only be driven slowly to get home. After checking the trouble codes, I found P0301 and P0302 indicating misfires on cylinders 1 and 2. I replaced the spark plugs, but the engine still misses when revved and the same P0301 and P0302 codes remain. The vehicle has an 1.8-liter engine. Any advice or troubleshooting steps would be greatly appreciated.
Spark plug coils are a very common issue on VW vehicles, especially in model years around 2004. These misfire codes (P0301 and P0302) typically point to faulty ignition coils for cylinders 1 and 2. It's worth noting that certain model years of the VW Passat had a known recall related to defective ignition coils. You can check if your vehicle is covered by this recall using your VIN number with the official VW customer service. As a DIY test, you could swap the spark plugs from cylinder #1 and #2 with those on cylinders #3 and #4. If the codes change to P0303 and P0304, it confirms that the issue is with the ignition coils. For long-term reliability, replacing all four ignition coils at once is recommended to prevent future misfires.