- Disconnect the fuel injector connector.
- Connect a test light between the positive terminal of the battery and the fuel injector connector terminal.
- Turn on the ignition.
- The test light should light up if the fuel injector is receiving power.
- If the test light does not light up, check the fuel injector fuse and relay.
- Replace the fuel injector if it is not receiving power.
2. Check the fuel pressure:
- Connect a fuel pressure gauge to the fuel rail.
- Turn on the ignition.
- The fuel pressure should be between 35 and 45 psi.
- If the fuel pressure is too low, check the fuel pump, fuel filter, and fuel pressure regulator.
- Replace the fuel injector if the fuel pressure is too high.
3. Check the compression:
- Remove the spark plug from the cylinder that is misfiring.
- Insert a compression tester into the spark plug hole.
- Crank the engine over until the compression gauge reads the highest pressure.
- The compression should be between 120 and 150 psi.
- If the compression is too low, the cylinder may be damaged.
4. Check the ignition timing:
- Connect a timing light to the number one spark plug wire.
- Start the engine and allow it to idle.
- Point the timing light at the timing marks on the engine.
- The timing marks should be aligned with the pointer on the timing cover.
- If the timing is off, adjust it according to the manufacturer's specifications.
5. If all of the above checks are normal, the cylinder may be misfiring due to a mechanical problem:
- Such as a worn piston ring or valve.
- In this case, the engine will need to be repaired or replaced.
