P0307 OBD-II Trouble Code: Cylinder 7 Misfire Detected

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0307 code

P0307 is a diagnostic trouble code (DTC) for "Cylinder 7 Misfire Detected". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $114.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford $114.99 $20.0
Toyota $114.99 $20.0
BMW $124.99 $20.0
SCHEDULE P0307 DIAGNOSTIC Get a fair and transparent estimate upfront

P0307 code definition

Cylinder 7 Misfire Detected

What the P0307 code means

When the P0307 diagnostic trouble code is stored by the Powertrain Control Module (PCM), it is an indication that a misfire has been detected in cylinder 7. More specifically, the PCM detects an increase or decrease in crankshaft revolutions per minute (RPM) that exceeds 2%.

A quick background into this system:

Each cylinder is connected to the crankshaft. On top of each cylinder is a spark plug, which uses a flammable fuel/air mixture that has been compressed inside the cylinder to fire a spark and set fire to the fuel. The fuel then releases energy to power the crankshaft. If the cylinders are not firing properly, there will be an increase or decrease in the crankshaft RPM.

What causes the P0307 code?

  • Faulty spark plug in cylinder 7
  • No compression in cylinder 7
  • Damaged or worn out spark plug wires
  • Damaged or worn spark plug coils
  • Damaged distributor cap (does not apply to all vehicles)
  • Damaged rotor button (does not apply to all vehicles)
  • Faulty fuel injector
  • Clogged exhaust gas recirculation (EGR) valves or tubes
  • Burned valves
  • Inaccurate ignition timing
  • Vacuum leaks
  • Low fuel pressure
  • Head gasket leaks
  • Cracked distributor cap
  • Faulty camshaft sensor
  • Faulty crankshaft sensor
  • Faulty mass air flow (MAF) sensor
  • Faulty oxygen (O2) sensor
  • Faulty throttle position sensor
  • Faulty catalytic converter
  • Faulty PCM

What are the symptoms of the P0307 code?

  • Check Engine Light that is on or flashing (dependant on severity of misfire condition)*
  • Vehicle that is difficult to start or will not start at all
  • Vehicles stalls during acceleration
  • Vehicle randomly stalls or dies at stops
  • Vehicle engine runs rough
  • Vehicle idles rough
  • Vehicle lacks power while driving
  • Increase of fuel consumption
  • Vehicle has no symptoms (rare)

*If the increase or decrease in crankshaft RPM is between 2-10%, the Check Engine Light will illuminate and remain steady. However, if the crankshaft RPM exceeds 10%, the Check Engine Light will illuminate and blink continuously. A variation of more than 10% in crankshaft RPM indicates a serious misfiring condition.

How does a mechanic diagnose the P0307 code?

  • Uses an OBD-II scanner to get all of the trouble codes and freeze frame data that has been stored by the PCM

  • Clears codes, then performs a test drive to see if code P0307 returns

  • Inspects the spark plug wire for cylinder 7 for wiring that is damaged or worn out

  • Inspects the spark plug for cylinder 7 for damaged or excessive wear

  • Inspects coil packs and coil pack wiring for corrosion, breaks, excessive wear, or other damage

  • Inspects the distributor cap and rotor button for corrosion, cracks, excessive wear, or other damage (if vehicle has distributor cap and rotor button system)

  • Replaces or repairs damaged spark plugs, coil packs, spark plug wiring, and/or coil pack wiring

  • Inspects the fuel injectors and fuel injector wiring if the P0307 code returns after any damaged spark plugs, coil packs, spark plug wires, and/or coil pack wiring has been replaced

  • Diagnoses and repairs any other trouble codes and performs another test drive to see if the P0307 code returns

  • If the P0307 code returns, inspects the compression system for cylinder 7

If clearing the P0307 diagnostic trouble code fails, the PCM may need to be replaced or reprogrammed. This is not common, but should be considered as a possibility when other diagnostic measures have not resolved the misfire condition.

Common mistakes when diagnosing the P0307 code

A common mistake is neglecting to rule out all of the possible causes for the misfire condition.

Visually inspect the fuel injector wiring before replacing spark plugs, spark plug wiring, coil packs, and coil pack wiring. In addition to ruling out the a faulty cylinder, other related stored trouble codes will need to be diagnosed and repaired. Taking time to address the other possible causes of the misfiring condition during the diagnostic process may save a lot of time.

How serious is the P0307 code?

A vehicle with a misfiring condition could shut down completely, or not start at all. These driveability issues make operation of a vehicle unreliable and hazardous. For this reason, the P0307 diagnostic trouble code is one that is considered serious. This condition should be addressed and repaired as soon as possible.

What repairs can fix the P0307 code?

Additional comments for consideration regarding the P0307 code

If one of the spark plugs is damaged and needs to be replaced, it will be necessary to replace all of the spark plugs. A good way to determine if a defective wire or coil pack is causing the misfire is to switch the wire and/or coil pack with another wire and/or coil pack. If a new trouble code comes back for a different cylinder, it is an indication that the misfiring condition is being caused by the wire and/or coil pack. It may also be possible that the vehicle is in need of a tune-up.

It is also necessary to gap the spark plugs properly, as not doing so can cause a misfiring condition. To gap the spark plugs correctly, a feeler gauge will be required. Manufacturer specifications should be used when gapping the spark plugs. These specifications can be found on a sticker, under the hood of the vehicle.

Need help with a P0307 code?

YourMechanic offers certified mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Light
trouble codes
P0307

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0307 code.

SCHEDULE P0307 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(7400)

Rating Summary
6879
249
58
41
173
6879
249
58
41
173
 at YourMechanic

David

13 years of experience
393 reviews
David
13 years of experience
Chevrolet Malibu L4-2.4L - Check Engine Light is on Inspection - Marietta, Georgia
He explained everything to me in detail on what I needed to know about my car. Definitely recommend him for getting the job done.
 at YourMechanic

Raymond

37 years of experience
402 reviews
Raymond
37 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Las Vegas, Nevada
Raymond did a great job however I was charged for two hours labor and he was only here less than 45 minutes. should I expect this on future appointments with your mechanic ?
 at YourMechanic

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Volkswagen EuroVan V6-2.8L - Check Engine Light is on Inspection - Austin, Texas
Arrived on time. Explained the issues he found and how he will fix it. I have parts on order and will schedule an appointment to have Shane install the parts when they arrive.
 at YourMechanic

Kanstantsin

19 years of experience
51 reviews
Kanstantsin
19 years of experience
Ford F-150 V8-4.6L - Check Engine Light is on Inspection - Littleton, Colorado
Kanstantsin arrived early. Was very courteous and professional. Will highly recommend to anyone. Thank you Kanstantsin.


Related questions

Keep getting multiple misfire codes, normally different cylinders except on cylinder (0307), can this one be throwing off the rest
This may be a problem with the exhaust catalyst partly clogged causing excessive back pressure. There is a test where the O2 sensor is removed and the back pressure tester is put in the hole to see if the catalyst...

More related articles

P2620 OBD-II Trouble Code: Throttle Position Output Circuit Open
P2620 P2620 code definition Throttle Position Output Circuit Open What the P2620 code means P2620 is an OBD-II code for the engine control module (ECM) detecting the throttle position closed output circuit is open and cannot detect a closed throttle....
P0720 OBD-II Trouble Code: Output Speed Sensor Circuit Malfunction
P0720 means there is an issue with the output speed sensor circuit. Issues may include engine stalling, misfiring and hesitation when accelerating.
P2573 OBD-II Trouble Code: Direct Ozone Reduction Catalyst Sensor Circuit Range/Performance
P2573 code means the sensors do not detect deterioration due to faulty catalyst, oxygen or temperature sensor, or lack of fuel or coolant.

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com