The buttery-smooth operation of your 2022 Mercedes-Benz E-Class has given way to an unsettling vibration, and the check engine light confirms something is wrong. A P0302 code—Cylinder 2 Misfire Detected—tells you exactly where the combustion problem is occurring, giving you a clear starting point for investigation.
Why Your E-Class Vibrates During a Misfire
Mercedes inline-four and inline-six engines are designed for exceptional smoothness through precise firing order and balance shaft systems. When cylinder 2 stops contributing to power production, this careful balance is disrupted. The engine vibration you feel is actually normal—it reveals how precisely engineered these engines are when operating correctly.
Common Causes of Cylinder 2 Misfire in the M254 Engine
The 2022 E-Class uses Mercedes' latest M254 four-cylinder with mild-hybrid technology. Cylinder-specific misfires typically stem from:
- Ignition coil failure - The coil-on-plug design means each cylinder has an individual coil that can fail independently
- Spark plug degradation - Carbon fouling, worn electrodes, or improper gap
- Direct fuel injector issues - Piezo injectors can develop deposits or electronic failures
- Low compression - Valve seating problems, head gasket issues, or cylinder wall damage
- Vacuum leak near cylinder 2 - Causes localized lean condition
- Wiring or connector problems - Intermittent connections to coil or injector
The Diagnostic Swap Test
The quickest way to identify ignition-related problems is the swap test:
- Record the current code (P0302 - Cylinder 2)
- Swap the ignition coil from cylinder 2 with cylinder 4
- Clear all fault codes
- Drive until the check engine light returns
- Read codes—if P0304 now appears, the moved coil is faulty
This same technique works for spark plugs. If the misfire code stays at cylinder 2 despite component swaps, investigate fuel delivery or compression.
Injector Considerations
Direct fuel injectors on Mercedes engines operate at extreme pressures and are precisely calibrated. While swapping is technically possible, it requires special tools and programming afterward. If you've ruled out ignition components, have the injectors professionally tested before replacement.
Repair Costs for 2022 E-Class Misfire
- Single ignition coil replacement: $180-$320
- Spark plug replacement (all four): $250-$400
- Fuel injector replacement: $450-$800 per injector
- Compression test: $100-$200
- Vacuum leak repair: $150-$400