Rough engine symptoms in your 2002 Ford Explorer with the 4.0L engine, such as misfires and poor idle, often stem from an incorrect firing order.
Correct Firing Order
The firing order for the 4.0L V6 engine is: 1-4-2-5-3-6. This sequence must match cylinder positions on the distributor or coil pack.
Common Symptoms
- Erratic or rough engine idle
- Noticeable hesitations or stalling during acceleration
- Excessive engine vibration and increased exhaust smoke
- Reduced fuel efficiency and potential engine code triggers
Troubleshooting Steps
- Inspect wiring: Check spark plug wires for damage, burns, or misrouting. Replace if cracked.
- Verify sequence: Trace wires from cylinder 1 to 6 in order 1-4-2-5-3-6. Refer to engine markings.
- Test components: Remove and inspect spark plugs for fouling or wear. Check coil pack/distributor function.
- Use a timing light: Attach to spark plug wires sequentially to confirm firing sequence and detect misfires.
- Reset if needed: Clear stored engine codes after repairs to ensure smooth operation.
Quick Fixes
For fast resolution:
- Realign wires to the correct firing order manually.
- Replace damaged spark plugs immediately—use stock gap specifications.
- Ensure ground connections are secure to avoid ignition issues.
Prioritize visual inspections to avoid common wiring errors and prevent recurrence.