Flashing Light = Stop Reading, Start Acting
A flashing check engine light is your 2022 Explorer's way of screaming. P0305—cylinder 5 misfire—combined with a flashing light means active misfires are occurring right now. Every moment you drive, unburned fuel is hitting your catalytic converters, potentially destroying thousands of dollars in emissions equipment.
Pull over safely and read this, but don't continue driving far.
What You're Experiencing
- Flashing check engine light
- Significant engine vibration
- Obvious loss of power
- Possible smell of unburned fuel
- Engine running on fewer than 6 cylinders
- May hear popping from exhaust
Cylinder 5 Location
On the 2.3L EcoBoost 4-cylinder Explorer... wait, there is no cylinder 5. If you have the 4-cylinder and see P0305, there may be a diagnostic glitch. On the 3.0L EcoBoost V6, cylinder 5 is on bank 2 (passenger side, rear position).
Urgent Causes of Cylinder 5 Misfire
Ignition Coil Failure
The coil-on-plug ignition coil for cylinder 5 has failed completely. No spark = no combustion. This is the most common single-cylinder failure.
Spark Plug Failure
The spark plug may have cracked, fouled severely, or have an electrode break. No reliable spark = misfire.
Fuel Injector Failure
A stuck-closed injector delivers no fuel. A stuck-open injector floods the cylinder. Either causes misfire.
Loss of Compression
Dropped valve, broken valve spring, or head gasket failure at cylinder 5. More serious and requires internal engine work.
Immediate Steps
- Stop driving - Pull over safely
- Let it idle briefly - See if steady light or flashing (flashing = shut off)
- Call for a tow - Safest option to prevent catalytic converter damage
- Or drive very carefully - If you must, go slowly, avoid acceleration, go straight to a shop
Repair Costs
- Ignition coil: $80 - $200
- Spark plug: $20 - $50
- Fuel injector: $200 - $450
- Catalytic converter (if damaged): $1,500 - $3,000+
- Internal engine repair: $2,000 - $6,000+
The Swap Test
If you have basic tools and a place to work:
- Swap cylinder 5's ignition coil with cylinder 4's
- Clear codes (or just note current code)
- Start the car (if it runs well enough)
- If misfire moves to P0304, the coil was bad
- If P0305 stays, try swapping spark plugs next
Catalytic Converter Warning
This is why we emphasize not driving: the 2022 Explorer has expensive catalytic converters. Unburned fuel igniting inside them can cause overheating and destruction in just a few minutes of driving. A $150 coil replacement becoming a $3,000+ repair is a painful lesson.