p0303
Easy Fix
Honda · SUVs
Cylinder 3 Misfire Detected
Quick Answer
Error code P0303 on your Honda SUVs means: Cylinder 3 Misfire Detected. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Worn or fouled spark plug in cylinder 3
  2. Failing ignition coil on cylinder 3
  3. Clogged or leaking fuel injector on cylinder 3
  4. Vacuum leak near cylinder 3 intake runner
  5. Low compression in cylinder 3
How to Fix It
1
Remove and inspect the cylinder 3 spark plug for wear, deposits, or incorrect gap; replace if needed
2
Swap the ignition coil from cylinder 3 with another cylinder, clear codes, and monitor to see if misfire follows the coil
3
Test the cylinder 3 fuel injector for proper resistance and verify it clicks when activated
4
Check for vacuum leaks near the cylinder 3 intake port using carb cleaner or a smoke machine
5
Perform a compression test on cylinder 3 and compare to other cylinders
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
Parts You May Need
Spark plug (NGK or Denso OEM-spec)
Ignition coil
Fuel injector
Intake manifold gasket
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