Your Coyote Has a Cough
The 5.0L Coyote V8 in your 2022 Mustang is supposed to deliver smooth, explosive power. When cylinder 6 starts misfiring and throws P0306, that symphony becomes a stumble. Cylinder 6 is on the passenger side, rear position—one of the harder-to-reach cylinders.
Let's track down what's killing your cylinder 6.
Symptoms You're Experiencing
- Rough idle or vibration
- Check engine light (may flash during hard acceleration)
- Loss of power, especially at higher RPM
- Possible exhaust popping or backfire
- Reduced fuel economy
- P0306 code stored
Cylinder 6 on the Coyote
Ford's cylinder numbering puts 1-4 on the passenger side (bank 1) and 5-8 on the driver side (bank 2). Wait—that means P0306 is on the driver side, not passenger. Cylinder 6 is driver side, middle-rear position. Access is moderate.
Common Causes of P0306
Failed Ignition Coil
The coil-on-plug ignition coil for cylinder 6 has failed. These are individual units on the Coyote and can fail independently. This is the most common cause.
Worn Spark Plug
Spark plugs on the Coyote work hard. A worn, fouled, or damaged plug can't ignite fuel reliably.
Fuel Injector Issue
A clogged or stuck injector doesn't deliver proper fuel. Direct injection injectors can clog over time.
Valve or Compression Issue
Low compression from valve problems, head gasket issues, or worn rings. Less common on a 2022 but possible if abused.
Wiring Problem
Damaged or corroded wiring to the coil or injector can cause intermittent misfires.
The Swap Test
- Swap the cylinder 6 ignition coil with cylinder 5's
- Clear codes
- Drive until misfire returns
- If code changes to P0305, the coil is bad
- If P0306 remains, try swapping spark plugs
Repair Costs
- Ignition coil: $50 - $150
- Spark plug: $15 - $40
- Spark plug set (all 8): $120 - $200
- Fuel injector: $150 - $350
- Fuel injector cleaning service: $150 - $300
- Compression test: $100 - $200
Flashing Light Warning
If your check engine light flashes during acceleration, you're having severe misfires. Stop accelerating hard immediately. Unburned fuel is going straight to your catalytic converters and can destroy them quickly. Drive gently to a shop.
Coyote Maintenance Note
The 5.0L Coyote benefits from regular spark plug replacement (every 60,000 miles or sooner if driven hard). Using quality coils and plugs (Motorcraft or equivalent) is important for the high-revving nature of this engine.