The P0307 OBD-II trouble code means the engine control module has detected a misfire associated with Cylinder 7.
Because P0307 identifies one cylinder, it provides a more focused starting point than P0300, which indicates random or multiple-cylinder misfires. It still does not identify the component responsible for the failure.
A worn spark plug, weak ignition coil, defective fuel injector, damaged circuit, intake leak, low compression, failed lifter, or worn camshaft can all trigger P0307.
The computer knows Cylinder 7 did not produce the expected power. It does not automatically know why—and replacing Coil 7 without testing it is still guessing, only with a receipt.
P0307 belongs to the misfire family covered in the complete Pro Street P-code OBD-II guide.
P0307 Quick Answer
| Item | Information |
|---|---|
| Trouble code | P0307 |
| Definition | Cylinder 7 Misfire Detected |
| System | Ignition and combustion |
| Severity | High |
| Safe to drive? | Only briefly if the misfire is mild and the Check Engine Light is not flashing |
| Most common causes | Spark plug, ignition coil, injector, wiring, intake leak, lifter, or low compression |
| Common applications | V8, V10 and V12 engines |
| Typical repair range | Approximately $30 to $7,000+, depending on the cause |
What Does the P0307 Code Mean?
P0307 breaks down as follows:
- P: Powertrain
- 0: Generic OBD-II code
- 3: Ignition or combustion misfire
- 07: Cylinder 7
The engine control module monitors tiny changes in crankshaft speed during individual combustion events. Each healthy cylinder accelerates the crankshaft slightly when combustion pushes its piston downward.
When Cylinder 7 repeatedly contributes less power than expected, the crankshaft briefly slows. The computer recognizes the pattern, stores P0307, and may illuminate or flash the Check Engine Light.
P0307 identifies the affected cylinder. It does not tell you whether the problem involves:
- Spark
- Fuel delivery
- Airflow
- Compression
- Valve operation
- Mechanical timing
- Electrical control
For a broader discussion of misfire behavior and warning signs, visit our engine misfire symptoms, causes and diagnosis guide.
Where Is Cylinder 7 Located?
P0307 applies to engines with at least seven cylinders, most commonly:
- V8 engines
- V10 engines
- V12 engines
- Certain specialty engines
Cylinder 7 location varies by manufacturer and engine family.
Some manufacturers place odd-numbered cylinders on one bank and even-numbered cylinders on the opposite bank. Others number the cylinders sequentially along each bank.
For example, Cylinder 7 may be:
- Near the rear of one cylinder bank
- Near the front of the opposite bank
- On the driver or passenger side
- Part of a cylinder-deactivation group
Do not assume Cylinder 7 is the seventh ignition coil you can reach.
Verify its location using:
- Factory service information
- Manufacturer repair manual
- Underhood emissions label
- Vehicle-specific firing-order diagram
- Correct engine identification code
This is especially important when one vehicle model offers several engines with different numbering systems.
Testing the wrong cylinder wastes time and can create a second misfire if a connector, plug wire, or coil boot is damaged in the process.
Common Symptoms Associated With P0307
The severity of a Cylinder 7 misfire depends on how often it occurs and under what operating conditions.
Drivers may notice:
- Illuminated Check Engine Light
- Flashing Check Engine Light
- Rough or unstable idle
- Engine shaking
- Hesitation
- Poor acceleration
- Reduced engine power
- Hard starting
- Stalling
- Increased fuel consumption
- Raw fuel smell from the exhaust
- Failed emissions test
- Popping from the intake or exhaust
- Reduced turbo or supercharger boost
- Limp mode
- Ticking or tapping from the valvetrain
- Additional ignition, injector, or fuel-trim codes
An intermittent P0307 may only appear during cold starts, idle, heavy acceleration, cylinder-deactivation operation, or high engine load.
The stored freeze-frame information can help identify when the failure occurs.
How Serious Is P0307?
P0307 should be treated as a high-priority trouble code.
An active misfire may send unburned fuel into the exhaust. That fuel can ignite inside the catalytic converter, causing the converter to overheat and fail.
Continued driving may also cause:
- Catalytic converter damage
- Oxygen sensor contamination
- Cylinder-wall fuel wash
- Engine oil dilution
- Burned exhaust valves
- Piston damage
- Excessive engine vibration
- Damaged engine or transmission mounts
- Reduced fuel economy
- Increased emissions
Stop Driving Immediately If:
- The Check Engine Light is flashing
- The engine is shaking violently
- Power loss is severe
- The vehicle stalls
- A strong raw-fuel smell is present
- The engine overheats
- Mechanical knocking is heard
- Loud ticking or abnormal valvetrain noise develops
A flashing Check Engine Light generally indicates a catalyst-damaging misfire. Reduce engine load, pull over safely, and shut the engine off.
If the light remains steady and the engine runs reasonably smoothly, driving a short distance for diagnosis may be possible. Avoid heavy throttle, high RPM, towing, and boost.
Most Common Causes of P0307
Cylinder 7 can misfire because of an ignition, fuel, electrical, airflow, compression, or valvetrain problem.
| Possible cause | Relative likelihood |
| Worn or fouled spark plug | Very high |
| Weak or failed ignition coil | Very high |
| Damaged coil boot or spark plug wire | High |
| Clogged or failed fuel injector | High |
| Coil or injector wiring fault | Medium |
| Intake manifold leak near Cylinder 7 | Medium |
| Low Cylinder 7 compression | Medium |
| Cylinder-deactivation lifter failure | Application dependent |
| Worn camshaft lobe | Application dependent |
| Carbon buildup on an intake valve | Medium on direct-injected engines |
| Burned or leaking valve | Medium |
| Damaged piston ring | Lower |
| Head gasket failure | Lower |
| Incorrect valve timing | Lower |
| PCM driver failure | Rare |
The vehicle, engine family, mileage, repair history, companion codes, and freeze-frame conditions should determine which possibility is tested first.
P0307 and Cylinder-Deactivation Problems
Cylinder 7 is particularly relevant on certain V8 engines equipped with cylinder-deactivation technology.
Depending on the manufacturer, these systems may be called:
- Active Fuel Management
- Dynamic Fuel Management
- Displacement on Demand
- Multi-Displacement System
- Variable Cylinder Management
These systems deactivate selected cylinders by controlling their valves, fuel injectors, or both. If Cylinder 7 is one of the controlled cylinders, a failed lifter, solenoid, oil passage, rocker arm, or camshaft lobe can cause P0307.
Warning signs include:
- P0307 returns after swapping coils
- Spark plug and injector test correctly
- Ticking or tapping is heard
- Cylinder 7 has low compression
- Valve lift is reduced
- Misfire appears during cylinder-mode transitions
- Oil-pressure or deactivation codes are stored
- Metal debris is found in the oil filter
A persistent P0307 on a cylinder-deactivation engine should not be treated as an automatic ignition-coil failure.
If Cylinder 7 has low valve lift, installing another coil will accomplish little beyond making the parts store slightly more profitable.
How to Diagnose P0307
Step 1: Confirm P0307
Connect an OBD-II scanner and record:
- Stored codes
- Pending codes
- Permanent codes
- Freeze-frame data
- Individual-cylinder misfire counters
Do not erase the code until the freeze-frame information has been saved.
Record:
- Engine RPM
- Engine load
- Vehicle speed
- Coolant temperature
- Intake-air temperature
- Short-term fuel trim
- Long-term fuel trim
- Throttle position
- Fuel-system status
- Cylinder-deactivation status where available
The operating conditions provide useful diagnostic direction.
| When P0307 occurs | Possible direction |
| Cold start | Leaking injector, carbon deposits, coolant intrusion, or weak compression |
| Warm idle | Intake leak, injector imbalance, or mechanical problem |
| Heavy acceleration | Weak coil, worn plug, excessive plug gap, or insufficient fuel |
| Wet weather | Coil boot, plug wire, or damaged insulation |
| During cylinder deactivation | Lifter, solenoid, oil-pressure, or camshaft problem |
| Constantly | Dead coil, injector fault, wiring problem, or compression loss |
| After recent service | Loose connector, incorrect plug, damaged wire, or installation mistake |
Step 2: Check for Related Trouble Codes
P0307 may appear with other misfire, fuel, ignition, or valvetrain codes.
Related codes include:
- P0300 — Random or Multiple Cylinder Misfire
- P0301 — Cylinder 1 Misfire
- P0302 — Cylinder 2 Misfire
- P0304 — Cylinder 4 Misfire
- P0305 — Cylinder 5 Misfire
- P0306 — Cylinder 6 Misfire
- P0308 — Cylinder 8 Misfire
- P0171 or P0174 — System Too Lean
- P0172 or P0175 — System Too Rich
- P0207 — Cylinder 7 Injector Circuit Malfunction
- P0357 — Ignition Coil G Primary/Secondary Circuit Malfunction
- Camshaft or crankshaft position codes
- Cylinder-deactivation or oil-pressure codes
Multiple cylinders misfiring together may indicate a shared problem such as:
- Low fuel pressure
- Contaminated fuel
- Large vacuum leak
- MAF sensor error
- Incorrect valve timing
- Charging-system problem
- Poor engine ground
- Crankshaft position signal fault
Step 3: Verify Cylinder 7
Use vehicle-specific information to locate Cylinder 7.
Inspect the surrounding area for:
- Disconnected coil or injector connectors
- Loose connector terminals
- Oil inside the spark plug well
- Coolant contamination
- Damaged wiring
- Rodent damage
- Cracked vacuum hoses
- Intake manifold leaks
- Harnesses touching exhaust components
- Loose engine grounds
If P0307 appeared immediately after maintenance or engine work, begin with a detailed visual inspection.
A partially connected ignition coil can impersonate catastrophic engine damage surprisingly well.
Step 4: Inspect the Cylinder 7 Spark Plug
Remove the Cylinder 7 spark plug and compare it with a plug from a healthy cylinder.
Look for:
- Worn electrodes
- Excessive gap
- Cracked porcelain
- Carbon fouling
- Oil contamination
- Wet fuel deposits
- Coolant deposits
- Overheating
- Incorrect heat range
- Incorrect plug type
- Improper torque
A wet plug may indicate that fuel is entering the cylinder but the mixture is not igniting.
A dry plug may suggest insufficient fuel delivery.
Oil deposits may indicate worn rings, valve-guide problems, PCV issues, or a leaking spark plug tube seal.
If the plugs are beyond their recommended service interval, replace the complete set using the correct type and gap.
Step 5: Swap the Cylinder 7 Ignition Coil
If the engine uses coil-on-plug ignition, move the Cylinder 7 coil to another cylinder.
For example, swap the Cylinder 7 and Cylinder 5 coils. Clear the codes and operate the engine under conditions similar to those recorded in the freeze-frame data.
If the code changes from:
P0307 to P0305
the ignition coil is likely defective.
If P0307 returns on Cylinder 7, the coil probably is not the cause.
Inspect the coil and boot for:
- Carbon tracking
- Cracks
- Moisture
- Oil contamination
- Corroded contacts
- Burned internal springs
- Damaged insulation
See our ignition coil replacement guide for additional testing and installation information.
Engines using distributor ignition, coil packs, or spark plug wires require a different procedure. Check wire resistance, routing, insulation, and coil output according to factory specifications.
Step 6: Understand P0307 Versus P0357
P0307 and P0357 describe related but different faults.
| Code | Meaning |
| P0307 | Combustion misfire associated with Cylinder 7 |
| P0357 | Electrical malfunction involving Ignition Coil G’s primary or secondary circuit |
P0357 provides stronger evidence of an ignition-coil circuit problem.
Possible P0357 causes include:
- Failed ignition coil
- Missing coil power
- Open trigger circuit
- Circuit shorted to ground
- Circuit shorted to voltage
- Loose connector terminal
- Corroded connector
- Failed PCM coil driver
P0307 without P0357 may still be caused by ignition, but fuel delivery, compression, airflow, and valvetrain operation must also be considered.
Coil letters commonly correspond with cylinder numbers, but manufacturer-specific information should always be checked before treating Coil G as Cylinder 7.
Step 7: Test the Cylinder 7 Fuel Injector
A clogged, leaking, stuck, electrically open, or unpowered injector can trigger P0307.
Listen to the Cylinder 7 injector with a mechanic’s stethoscope and compare its sound with the other injectors.
Further testing may include:
- Injector resistance measurement
- Injector voltage test
- Noid-light test
- Injector current-ramp test
- Injector balance test
- Fuel-pressure drop test
- Injector swap test where practical
Use the manufacturer’s injector resistance and circuit specifications.
Pro Street injector-testing resources include:
- How to Test a Ford Ranger Fuel Injector
- How to Test Nissan Altima Fuel Injectors
- How to Test a Toyota Corolla Fuel Injector
- How to Test an Acura RSX Fuel Injector
Never open a gasoline direct-injection or diesel common-rail fuel system without following the manufacturer’s pressure-relief procedure.
Step 8: Inspect the Coil and Injector Circuits
If the coil and injector test correctly, inspect their circuits.
Check for:
- Correct supply voltage
- Reliable ground
- Ignition-coil trigger signal
- Injector control pulse
- Loose terminal tension
- Corroded pins
- High circuit resistance
- Wiring shorted to ground
- Wiring shorted to voltage
- Harness damage
- Poor engine or PCM grounds
Use voltage-drop testing while the circuit is operating whenever possible.
A wire may pass a continuity test while failing under load. This is why a multimeter’s beep is not the final ruling from the Supreme Court of Automotive Diagnosis.
PCM failure is possible but rare. Verify the component, wiring, power supply, grounds, and mechanical condition first.
Step 9: Check for an Intake Leak
An intake leak near the Cylinder 7 runner can create a localized lean condition.
Inspect:
- Intake manifold gasket
- Cylinder 7 injector seal
- Vacuum hoses
- PCV system
- Brake-booster hose
- Intake manifold
- Throttle-body gasket
A smoke test is generally the safest and most effective method for locating an intake-system leak.
Fuel-trim data can provide another clue. Strongly positive fuel trim at idle that improves as RPM increases frequently indicates a vacuum leak.
Step 10: Perform a Compression Test
If Cylinder 7 has spark, fuel, and correct electrical control, test its compression.
Compare Cylinder 7 with the other cylinders and use the manufacturer’s minimum pressure and allowable variation.
Low compression may be caused by:
- Burned intake valve
- Burned exhaust valve
- Bent valve
- Worn piston rings
- Damaged piston
- Broken valve spring
- Collapsed lifter
- Failed cylinder-deactivation lifter
- Worn camshaft lobe
- Head gasket failure
- Cylinder-wall damage
- Incorrect valve timing
If Cylinder 7 compression is low, continue with a leak-down test.
Step 11: Perform a Cylinder Leak-Down Test
Position Cylinder 7 at top dead center on its compression stroke and introduce regulated compressed air.
| Air heard or observed at | Likely fault |
| Throttle body or intake | Leaking intake valve |
| Exhaust outlet | Leaking exhaust valve |
| Oil filler opening | Piston rings or cylinder damage |
| Cooling system | Head gasket, cylinder head, or block damage |
| Adjacent cylinder | Head gasket failure between cylinders |
Leak-down testing helps separate an ignition or fuel-delivery problem from internal engine damage.
Step 12: Inspect Cylinder 7 Valve Operation
If compression is low or valvetrain noise is present, inspect valve movement.
Depending on the engine, diagnosis may include:
- Removing the valve cover
- Comparing rocker-arm movement
- Measuring valve lift
- Inspecting pushrods
- Testing cylinder-deactivation solenoids
- Verifying engine oil pressure
- Inspecting the camshaft with a borescope
- Checking the oil filter for metal debris
Reduced valve lift on Cylinder 7 may indicate a failed lifter or worn camshaft lobe.
Step 13: Check for Intake-Valve Deposits
Direct-injected engines may develop deposits on their intake valves because fuel no longer flows across the back of each valve.
Uneven deposits near Cylinder 7 may cause:
- Cold-start P0307
- Rough idle
- Airflow imbalance
- Misfire that improves after warm-up
A borescope inspection can help confirm the problem. Approved cleaning procedures vary and may include media blasting or professional chemical cleaning.
Step 14: Clear P0307 and Verify the Repair
After repairing the confirmed fault:
- Clear stored and pending codes.
- Start the engine.
- Verify a stable idle.
- Monitor Cylinder 7 misfire counters.
- Recreate the original freeze-frame conditions when safe.
- Complete the required drive cycle.
- Scan for pending codes.
- Confirm that readiness monitors complete normally.
The repair is confirmed when Cylinder 7 misfire counts remain normal and P0307 does not return.
Common P0307 Repairs and Costs
Actual costs depend on the vehicle, labor rate, component accessibility, and underlying failure.
| Repair | Approximate installed cost |
| Replace spark plugs | $50–$600 |
| Replace one ignition coil | $80–$500 |
| Replace plug wire or coil boot | $30–$300 |
| Clean or replace one injector | $150–$1,200 |
| Repair wiring or connector | $100–$800 |
| Repair intake or vacuum leak | $100–$1,000 |
| Intake-valve carbon cleaning | $400–$1,500 |
| Replace intake manifold gasket | $400–$1,800 |
| Replace failed lifter or camshaft | $1,500–$7,000+ |
| Cylinder-head or valve repair | $1,500–$6,000+ |
| Engine replacement | $5,000–$20,000+ |
P0307 can represent anything from an inexpensive spark plug to significant valvetrain damage. Diagnose the failure before pricing the repair.
Common P0307 Diagnostic Mistakes
Replacing Coil 7 Without Testing It
Swap the coil with another cylinder. If the misfire follows the coil, replace it. If P0307 remains, keep diagnosing.
Testing the Wrong Cylinder
Cylinder numbering varies considerably among V8, V10, and V12 engines. Verify the correct layout before removing components.
Confusing P0307 With P0357
P0307 is a combustion-misfire code. P0357 identifies an electrical fault involving Ignition Coil G’s circuit.
Ignoring Cylinder-Deactivation Hardware
On applicable engines, a failed lifter, solenoid, oil passage, rocker arm, or camshaft can cause a persistent P0307.
Replacing the Injector Without Testing It
Confirm injector power, control and fuel delivery before replacement.
Clearing Freeze-Frame Data Too Early
Freeze-frame information may be the only record of the operating conditions that triggered P0307.
Skipping Compression Testing
If the plug, coil, injector and circuits test correctly, verify the mechanical condition of Cylinder 7.
Replacing the Catalytic Converter First
The converter may have been damaged by the misfire. Correct P0307 before evaluating catalyst efficiency.
P0307 Frequently Asked Questions
Does P0307 Mean the Cylinder 7 Ignition Coil Is Bad?
No. A failed coil is common, but P0307 may also result from a spark plug, injector, wiring, intake, compression, lifter, or camshaft problem.
Can P0357 Cause P0307?
Yes. P0357 identifies an electrical malfunction involving Ignition Coil G, which commonly corresponds with Cylinder 7. Verify the manufacturer’s coil assignment before testing.
Can a Spark Plug Cause P0307?
Yes. A worn, cracked, fouled, overheated, or incorrectly gapped Cylinder 7 spark plug is one of the most common causes.
Can a Fuel Injector Cause P0307?
Yes. A clogged, leaking, stuck, electrically failed, or unpowered Cylinder 7 injector can cause a cylinder-specific misfire.
Can a Vacuum Leak Affect Only Cylinder 7?
Yes. An intake manifold gasket or injector-seal leak near the Cylinder 7 runner may create a localized lean condition.
Can a Failed Lifter Cause P0307?
Yes. A collapsed or failed lifter can prevent the Cylinder 7 valves from opening correctly. This is especially relevant on some cylinder-deactivation V8 engines.
Can a Worn Camshaft Trigger P0307?
Yes. A worn Cylinder 7 camshaft lobe may reduce valve lift and cause low compression, poor airflow, and a persistent misfire.
Why Does P0307 Only Appear Under Acceleration?
A weak coil, worn plug, excessive plug gap, injector restriction, or fuel-pressure problem may only become noticeable as cylinder pressure and engine load increase.
Why Does P0307 Appear During a Cold Start?
Possible causes include a leaking injector, intake-valve deposits, coolant intrusion, low compression, or a temperature-sensitive electrical fault.
Can I Drive With P0307?
Only briefly if the engine runs reasonably smoothly and the Check Engine Light remains steady. Stop driving if the light flashes, the engine shakes severely, power drops, or raw fuel can be smelled.
Can P0307 Damage the Catalytic Converter?
Yes. Unburned fuel can overheat and destroy the catalytic converter.
Will P0307 Clear Itself?
The Check Engine Light may turn off after several successful drive cycles, but stored or permanent code data may remain until the vehicle completes the required self-tests.
Related Misfire and Ignition Codes
- P0300 — Random or Multiple Cylinder Misfire
- P0301 — Cylinder 1 Misfire
- P0302 — Cylinder 2 Misfire
- P0303 — Cylinder 3 Misfire
- P0304 — Cylinder 4 Misfire
- P0305 — Cylinder 5 Misfire
- P0306 — Cylinder 6 Misfire
- P0307 — Cylinder 7 Misfire
- P0308 — Cylinder 8 Misfire
- P0316 — Misfire Detected During Startup
- P0207 — Cylinder 7 Injector Circuit Malfunction
- P0357 — Ignition Coil G Primary/Secondary Circuit Malfunction
Explore the Pro Street OBD-II Code Libraries
Use the Pro Street cornerstone pages to find additional diagnostic trouble codes:
- All P OBD-II Codes Explained — Powertrain Codes
- All B OBD-II Codes Explained — Body and SRS Codes
- All C OBD-II Codes Explained — Chassis Codes
- OBD-II DTC Doctor
P0307 identifies a misfire associated with Cylinder 7. Begin by saving the freeze-frame data and verifying the correct cylinder location. Inspect the spark plug, swap-test the coil, and test the injector and circuits.
If the misfire remains on Cylinder 7, inspect for intake leaks and verify compression, valve movement, lifter operation, and camshaft condition.
Replacing parts is easy. Proving which part failed is the step that keeps the same Check Engine Light from returning two days later.