P0307 on Jeep
Cylinder 7 Misfire Detected
P0307 on Jeep vehicles indicates cylinder 7 misfire detected. Au7o has documented this code across 2 Jeep models — most commonly on Commander, Grand Cherokee. P0307 means the engine computer detected a misfire on cylinder number 7 — that cylinder isn't burning its air/fuel mixture completely or at the right moment. The PCM senses this by watching for tiny slowdowns in crankshaft speed each time cylinder 7 should fire. A misfire wastes fuel, can dump raw fuel into the exhaust, and may damage the catalytic converter over time, which is why a persistent or severe misfire often makes the check engine light flash. You may feel rough idle, shaking, hesitation, or a loss of power. Typical repair costs on Jeep range from $2,200 to $7,500, depending on the specific model and root cause.
Common Causes of P0307
- •Worn, fouled, or incorrectly gapped spark plug on cylinder 7
- •Failed ignition coil or coil-on-plug for cylinder 7
- •Faulty, clogged, or leaking fuel injector
- •Vacuum or intake air leak affecting that cylinder
- •Low compression (worn rings, burnt/leaking valve, head gasket)
- •Damaged spark plug wire or boot (on applicable engines)
- •Carbon buildup or sticking valve
P0307 on Jeep by Model
Jeep Commander(1 issue)
- 4.7L PowerTech V8 Dropped Valve Seat / Cracked Cylinder Head Causing Sudden Single-Cylinder Misfire2006-2009
The 4.7L SOHC PowerTech V8 (2006-2009 Commander) presses hard steel valve seats into aluminum cylinder heads. Any overheat event - and the XK's cooling system is itself a weak point - lets the aluminum head grow away from the seat, loosening it. The seat then drops into the combustion chamber, or the head cracks between the valve seats. The failure is usually sudden: a healthy-running engine develops a violent single-cylinder misfire, a hammering noise and total loss of compression in that hole within minutes. Commander owners report it most often on the 4.7 after a cooling-system incident, and Chrysler's 2005-2007 4.7 heads are the ones most cited. Compression on the dead cylinder reads near zero; a borescope shows the seat lying on the piston crown or a valve pocket that has been pounded out.
Jeep Grand Cherokee(1 issue)
- HEMI Engine Tick/Lifter Noise2011-2021
HEMI-equipped Grand Cherokees can develop the characteristic MDS lifter tick. This ticking noise is most noticeable at idle and during light throttle. While often not immediately harmful, it indicates lifter wear from the MDS cylinder deactivation system.
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View P0307 across all makes →Frequently Asked Questions
What does P0307 mean on Jeep?▼
P0307 stands for "Cylinder 7 Misfire Detected." P0307 means the engine computer detected a misfire on cylinder number 7 — that cylinder isn't burning its air/fuel mixture completely or at the right moment. The PCM senses this by watching for tiny slowdowns in crankshaft speed each time cylinder 7 should fire. A misfire wastes fuel, can dump raw fuel into the exhaust, and may damage the catalytic converter over time, which is why a persistent or severe misfire often makes the check engine light flash. You may feel rough idle, shaking, hesitation, or a loss of power. On Jeep specifically, this code is documented across 2 models.
What causes P0307 on Jeep vehicles?▼
Common causes on Jeep: Worn, fouled, or incorrectly gapped spark plug on cylinder 7, Failed ignition coil or coil-on-plug for cylinder 7, Faulty, clogged, or leaking fuel injector, Vacuum or intake air leak affecting that cylinder, Low compression (worn rings, burnt/leaking valve, head gasket). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0307 on a Jeep?▼
Repair costs on Jeep range from $2,200 to $7,500, depending on the specific model and root cause.
Which Jeep models have P0307 documented?▼
Au7o has documented P0307 on 2 Jeep models: Commander, Grand Cherokee.