P0303 is an error code that typically indicates that there is a problem with the cylinder 3 misfire. This means that the cylinder is not firing correctly, and as a result, the engine is not running as efficiently as it should be. There are a number of reasons why this might happen, including a problem with the spark plugs, the ignition system, or the fuel system. In some cases, it can also be caused by a leak in the exhaust system.
Users typically search for a solution by asking about:
- error code p0303
- p0303 engine code
1. Check the spark plugs and wires
- Remove the spark plugs from the engine. This can be done using a spark plug socket or a wrench. Make sure the gap is at .030 inch and that the threads are clean.
- Check the wires for cracks, cuts, or wear. Make sure they are not twisted or kinked. If there are any problems, replace the wires.
- Reinstall the spark plugs and tighten the bolts to 20 foot-pounds (22 Nm).
2. Check the injectors
- Remove the fuel filter
- Pry open the injectors with a flathead screwdriver
- Clean the injectors using a fuel cleaner and a brush
- Replace the injectors if necessary
3. Check for vacuum leaks
- Start the engine and allow it to idle for a few minutes.
- Check the vacuum lines and hoses for any leaks.
- Check the engine vacuum port to determine if there is any vacuum loss.
- Repair or replace any vacuum leaks.
4. Check the EGR valve
- Remove the air cleaner element.
- Check the fuel filter for blockages.
- Check the EGR valve for proper function.
- Clean and inspect the engine parts.
Some users might also have success with the following opitons:
- Check the ignition coil.
- Check the fuel pressure.
- Check for a blown head gasket.
- Check the PCV valve.
- Check the compression.