what does it mean if my Toyota Highlander is throwing P0302 misfire code?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, compression tester, multimeter, fuel injector tester
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Replace Spark Plug and Ignition Coil

1. Disconnect the negative battery terminal.
2. Remove the engine cover if necessary to access the ignition coil.
3. Remove the ignition coil from cylinder 2 by unscrewing the retaining bolts.
4. Remove the spark plug using a spark plug socket and ratchet, ensuring to note the condition of the old spark plug.
5. Install the new spark plug to the manufacturer’s torque specification (typically 13-15 ft-lbs).
6. Reinstall the ignition coil onto the new spark plug and secure it with the retaining bolts.

3. Check and Replace Fuel Injector (if necessary)

1. Disconnect the fuel injector electrical connector and fuel line (use caution as fuel may spill).
2. Remove the fuel injector retaining clips and pull out the injector.
3. Inspect the old injector for clogs or damage. If faulty, replace with a new injector.
4. Install the new fuel injector by reversing the removal process, ensuring it is seated properly.

4. Compression Test (if misfire persists)

1. Remove the spark plug again.
2. Insert the compression tester into the spark plug hole for cylinder 2.
3. Crank the engine for a few seconds and read the compression value.
4. If the compression is below specs (typically around 150 psi), consider further diagnosis for potential engine issues (e.g., valve problems, head gasket failure).