How to solve P0301 misfire in cylinder 1?
2 Answers
If the P0301 misfire (cylinder 1) current trouble code appears, generally speaking, it is necessary to remove the spark plug and ignition coil for inspection. The solution to this problem should be to replace the ignition coil, cylinder wire, and spark plug. If considering deeper-level causes for cylinder misfire, the following points can be considered: 1. Whether the mixture concentration is abnormal, as excessively high or low mixture concentration may cause the trouble code to appear. 2. Whether the intake air volume is insufficient. 3. Whether the fuel injection pulse width is abnormal. 4. Whether the oxygen sensor heating and air flow sensor are abnormal, and whether the connector is damaged. 5. Whether there is a conflict between ignition correction and fuel injection correction. 6. Whether the throttle position sensor signal is reliable.
My car also had the P0301 trouble code before, and misfire in cylinder 1 is indeed a common issue. Based on my experience, the first thing to check is the spark plugs - if the electrodes are severely eroded, they should be replaced. Ignition coils are particularly prone to failure too, you can try swapping them with other cylinders for testing. Clogged fuel injectors can also cause misfires, especially when using ethanol-blended gasoline in northern regions which is more likely to clog. Additionally, a dirty crankshaft position sensor can affect signal reading - cleaning it with carburetor cleaner usually solves the problem. If none of these are the issue, then cylinder compression needs to be tested - if it's below standard values, you should suspect valve or piston ring problems. Last time I fixed this fault, it took me three days to finally identify it as aging fuel injector O-rings causing fuel leaks, so patience is key for systematic troubleshooting.
