Ignition & misfire · Powertrain · generic (SAE-defined)
P0307: Cylinder 7 Misfire Detected
P0307 means the engine computer detected misfires in cylinder 7, which applies to engines with seven or more cylinders, most often V8s.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0307 sets
Using the crankshaft position sensor, the powertrain control module (PCM) detects the speed dip that follows a missed combustion event. When cylinder 7 accumulates enough misfires within a manufacturer-set window, P0307 is recorded.
Common causes of P0307
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- Ignition coil or spark plug wire failure on cylinder 7
- Worn or fouled spark plug
- Cylinder 7 fuel injector problem
- Damaged wiring to the cylinder 7 coil or injector
- Intake leak near cylinder 7
- Valvetrain issue such as a collapsed lifter or worn cam lobe
P0307 symptoms
- Check engine light on or flashing
- Rough idle
- Ticking or tapping noise if a lifter is involved
- Reduced power and fuel economy
How P0307 is diagnosed
- Read freeze frame data and check other misfire codes on the same bank.
- Inspect and swap the cylinder 7 coil or plug wire.
- Inspect the spark plug for fouling or damage.
- Check injector operation and wiring.
- Listen for valvetrain noise and perform compression or leak-down testing if needed.
Typical fixes for P0307
- Replace the cylinder 7 coil or plug wire
- Replace spark plugs
- Repair or replace the cylinder 7 injector
- Repair wiring faults
- Replace failed lifters or camshaft if confirmed
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Manufacturer notes
On some V8 engines with cylinder deactivation, lifter failures in the deactivated cylinders are commonly reported as a cause of misfire codes.
Related codes & warning lights
P0307 FAQ
What does code P0307 mean?
P0307 means the engine computer detected misfires in cylinder 7, which applies to engines with seven or more cylinders, most often V8s. The standard definition is "Cylinder 7 Misfire Detected."
Can I drive with a P0307 code?
Usually yes for short, easy drives if the light is steady and the engine runs acceptably. A flashing check engine light means the misfire is severe; stop driving soon to protect the catalytic converter.
Can a lifter problem cause P0307?
Yes. On some V8 engines, a collapsed or stuck lifter prevents a valve from opening properly, causing a misfire often accompanied by a ticking noise.
Do cylinder deactivation systems affect P0307?
On engines that shut off cylinders to save fuel, faults in the deactivation hardware can cause misfires in the affected cylinders. Diagnosis follows manufacturer procedures.
Keep researching
Engine guides by brand (known issues, specs)
More ignition & misfire codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.