P0307: Cylinder 7 Misfire Detected

What does P0307 mean?

Cylinder 7 is misfiring. This code applies to V8 and larger engines. Where cylinder 7 sits depends on the maker's numbering scheme (some number down one bank and then the other, others alternate), so check a diagram first. Rear cylinders on some V8s run hotter, which can be hard on plugs and coils.

Generic OBD-II definition: Cylinder 7 Misfire Detected. Confirm applicability in your vehicle service information.

Common causes

• Spark plug for cylinder 7 worn or broken
• Coil or plug wire for cylinder 7 failing (on engines with wires, a wire close to the exhaust can burn)
• Cylinder 7 injector problem
• Exhaust manifold heat damaging nearby wiring
• Worn valve train or low compression

Symptoms

• Noticeable shake at idle
• Popping from the exhaust
• Flashing check engine light under acceleration

Can I keep driving with P0307?

Severity: High Stop or minimize driving and get it looked at right away.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Confirm cylinder 7's location for your engine family
• If your engine uses plug wires, check the cylinder 7 wire for burns where it passes the exhaust manifold
• Swap cylinder 7's ignition coil with a neighboring cylinder's coil, clear codes, and drive: if the code moves to that cylinder, the coil is bad
• Check injector resistance and connector if ignition checks out