Where is cylinder 7 on a V8?

It depends on the manufacturer. GM V8s (Chevrolet, GMC) put cylinders 1, 3, 5 and 7 on the left bank from front to back, so cylinder 7 is the rearmost cylinder on that side. Ford V8s number the right bank 1 to 4 and the left bank 5 to 8, so cylinder 7 is the third cylinder back on the left. European V8s follow their own numbering, so check the service data or a diagram before swapping parts.

Can I drive with a P0307 code?

Only gently and only as far as a workshop, and not at all if the check engine light is flashing. A flashing light means the misfire is severe enough to send unburned fuel into the catalytic converter, which overheats and can fail. A steady light gives you a little more time, but the fault will not clear itself.

What is the most common cause of a cylinder 7 misfire?

A worn spark plug or a failing ignition coil on that cylinder, which is why the free coil swap test is the first step. If the misfire does not follow the coil, the injector, an intake leak and the engine's mechanical condition on that cylinder come next.

I replaced the plug and coil but P0307 came back. What next?

Move to fuel, air and mechanics. Test or swap the cylinder 7 injector, smoke-test the intake for leaks, and run a compression test. On GM V8s with Active Fuel Management, cylinder 7 is one of the cylinders the system shuts down, and a sticking or collapsed lifter there is a documented cause of a misfire that no coil or plug will fix.

How much does it cost to fix P0307?

Most fixes are a coil or a set of plugs, typically about €70 to €330 fitted at an independent workshop. A plug set on a V8 costs more than on a four-cylinder because there are eight plugs and some sit under intake parts. Injector work costs more, and a mechanical fault such as a lifter or valve is the expensive outcome, which is why it pays to rule out the cheap causes first.

P0307: Cylinder 7 Misfire Detected

Quick Answer

Not safe to drive

P0307 means the engine computer has counted repeated misfires on cylinder 7. The code can only appear on engines with at least seven cylinders, which in practice means V8s, V10s and V12s. The usual culprits are the cylinder 7 spark plug or ignition coil, followed by the injector, an intake leak and, less often, a mechanical fault in that cylinder.

Severity: High · Misfire
Estimated repair cost: From €55 to €2700+, varies by vehicle

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What does P0307 mean?

P0307 is a misfire-related diagnostic trouble code classified as high severity. When your vehicle's ECU detects this condition, it stores P0307 and illuminates the check engine light.

What are the symptoms of P0307?

If your vehicle has triggered P0307, you may notice one or more of these symptoms:

Check engine light on, flashing while the misfire is active under load
Rough, uneven idle that a healthy V8 does not normally have
Hesitation and loss of power when accelerating, climbing or towing
Higher fuel consumption than usual
Raw fuel smell or popping from the exhaust
A ticking noise from the top of the engine when the cause is a lifter or valve on cylinder 7

What causes P0307?

Here are the most common causes of P0307:

Worn or fouled spark plug on cylinder 7
: high
Failed ignition coil on cylinder 7
: high
Clogged, leaking or electrically failed fuel injector on cylinder 7
: medium
Vacuum leak at the intake runner, gasket or a hose near cylinder 7
: medium
Carbon deposits on the intake valves of a direct-injection engine restricting airflow into the cylinder
: medium
Collapsed lifter, worn cam lobe or low compression on cylinder 7
: low

Is it safe to drive with P0307?

No - address this immediately. With a steady check engine light you can drive gently to a workshop, but a flashing light means unburned fuel is reaching the catalytic converter on that bank. If it flashes, stop driving and have the car recovered rather than turn a coil or plug job into a converter replacement.

How do you diagnose P0307?

Follow these steps to pinpoint the root cause of P0307:

Read all stored and pending codes plus the freeze frame. Note whether other cylinders also log misfires and whether lean codes (P0171, P0174) or camshaft correlation codes (P0016 to P0019) are stored, because those point to a shared cause rather than one cylinder.
Find cylinder 7 in the service data for your engine before removing anything. V8 numbering differs by maker: GM puts the odd-numbered cylinders on the left bank, while Ford numbers one bank 1 to 4 and the other 5 to 8.
Pull the cylinder 7 coil and plug. Oil on the plug points to valve stem seals or rings, black soot to a rich mixture, and a cracked or blistered insulator to a plug that has overheated.
Swap the cylinder 7 coil with one from a neighbouring cylinder, clear the codes and drive. If the misfire moves with the coil, replace the coil.
If the misfire stays on cylinder 7, check the injector. On port-injected engines you can listen for its click with a stethoscope; direct injectors run at very high pressure and are best tested by a workshop.
Watch live fuel trims for the bank containing cylinder 7. A lean trim on that bank alone points to an intake leak or a weak injector on that side; a smoke test finds the leak.
If ignition and fuel check out, run a compression and leak-down test on cylinder 7. A reading clearly below the other cylinders means valve, ring or lifter trouble.
After the repair, clear the codes and drive a mix of idle, steady cruising and acceleration, then check that no misfire code returns.

How much does P0307 cost to fix?

Repair costs for P0307 vary depending on the root cause and your vehicle. Here are typical estimates:

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Replace spark plug on cylinder 7 (on a V8 usually the full set of eight)	€15–€120	€40–€200	€55–€320	Moderate
Replace ignition coil on cylinder 7	€40–€180	€30–€150	€70–€330	Easy
Clean or replace fuel injector on cylinder 7	€60–€250	€80–€150	€140–€400	Professional
Intake manifold gasket or vacuum hose repair	€40–€150	€150–€400	€190–€550	Moderate
Cylinder head, valve or lifter work after a failed compression or leak-down test	€300–€1200	€400–€1500	€700–€2700	Professional

Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.

Full repair guides

P0307 on specific vehicles

P0307 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

P0307 on Chevrolet

Chevrolet Silverado 1500 5.3 V8 (Gen IV, AFM)

See Chevrolet-specific causes & cost

P0307 on BMW

BMW 5 Series 545i / 550i (N62 V8) · BMW X5 xDrive50i (N63 twin-turbo V8)

See BMW-specific causes & cost

P0307 on Audi

Audi S5 Coupe (B8, 4.2 FSI V8)

See Audi-specific causes & cost

P0307 on Mercedes-Benz

Mercedes-Benz S500 / S550 (W221, M273 V8)

See Mercedes-Benz-specific causes & cost

These codes are often seen alongside P0307 or indicate related issues:

Common questions about P0307

Where is cylinder 7 on a V8?: It depends on the manufacturer. GM V8s (Chevrolet, GMC) put cylinders 1, 3, 5 and 7 on the left bank from front to back, so cylinder 7 is the rearmost cylinder on that side. Ford V8s number the right bank 1 to 4 and the left bank 5 to 8, so cylinder 7 is the third cylinder back on the left. European V8s follow their own numbering, so check the service data or a diagram before swapping parts.
Can I drive with a P0307 code?: Only gently and only as far as a workshop, and not at all if the check engine light is flashing. A flashing light means the misfire is severe enough to send unburned fuel into the catalytic converter, which overheats and can fail. A steady light gives you a little more time, but the fault will not clear itself.
What is the most common cause of a cylinder 7 misfire?: A worn spark plug or a failing ignition coil on that cylinder, which is why the free coil swap test is the first step. If the misfire does not follow the coil, the injector, an intake leak and the engine's mechanical condition on that cylinder come next.
I replaced the plug and coil but P0307 came back. What next?: Move to fuel, air and mechanics. Test or swap the cylinder 7 injector, smoke-test the intake for leaks, and run a compression test. On GM V8s with Active Fuel Management, cylinder 7 is one of the cylinders the system shuts down, and a sticking or collapsed lifter there is a documented cause of a misfire that no coil or plug will fix.
How much does it cost to fix P0307?: Most fixes are a coil or a set of plugs, typically about €70 to €330 fitted at an independent workshop. A plug set on a V8 costs more than on a four-cylinder because there are eight plugs and some sit under intake parts. Injector work costs more, and a mechanical fault such as a lifter or valve is the expensive outcome, which is why it pays to rule out the cheap causes first.

Read our detailed guides

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