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  • The P0307 code stands for “Cylinder #7 Misfire Detected,” which means there’s an incomplete combustion happening inside cylinder #7, causing it to misfire.
  • A bad ignition coil, a faulty injector, and an internal engine problem are some possible causes of the P0307 code.
  • Some common symptoms associated with the P0307 code include a hard-starting engine, an illuminated check engine light, and engine hesitation.

An engine misfire is a common drivability problem that car owners may experience at one point. Once your vehicle’s primary computer detects an engine misfire, it will most likely turn on the check engine light.

There are several OBD-II diagnostic trouble codes related to engine misfires. In this article, we will talk about the OBD code P0307.

What Does the P0307 Code Mean?

Diagnostic trouble code (DTC) P0307 stands for “Cylinder #7 Misfire Detected.” It indicates that your vehicle’s cylinder #7 is misfiring. This means that incomplete combustion is happening inside the cylinder.

Cylinder number 7 refers not to the seventh cylinder in the firing order, but the cylinder numbered “7” in the arrangement of cylinders on the engine.

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mechanic obd code
The definition of Code P0307 may vary depending on the vehicle manufacturer.

Cylinder number 7 refers not to the seventh cylinder in the firing order, but the cylinder numbered “7” in the arrangement of cylinders on the engine.

– Richard McCuistian, ASE Certified Master Automobile Technician

Remember that the efficient burning of air and fuel is essential to engine operation. Without the proper combustion of the air/fuel mixture, the engine won’t run properly or won’t run at all.

If you need help locating cylinder #7, read our explanation about cylinder location and firing order. An in-depth understanding of cylinder misfires can also help you correctly diagnose the issue and come up with a solution if you’re planning a DIY fix.

Note: The definition of Code P0307 may vary depending on the vehicle manufacturer. It is best to consult your trusted repair manual or repair database for the exact code definition.

P0307 on Some Ford Vehicles

Code P0307 may appear on some Ford vehicles. On a 2013 Ford F-150 XL 5.0L V8, for example, the code appears because of the following conditions:

  • Issues with the ignition system
  • Faulty fuel injectors
  • Running out of fuel
  • Issues with the EVAP purge valve
  • Fuel pressure problem
  • Issues with the EVAP system
  • Issues with the Exhaust gas recirculation (EGR) system
  • Base engine problem
  • Misfire monitor neutral profile correction has not been relearned since the last mechanical repair
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For this specific vehicle, Ford also notes that the malfunction indicator lamp (MIL) blinks once per second when a misfire severe enough to cause catalyst damage is detected. If the MIL is on steady state due to a misfire, this indicates the threshold for emissions was exceeded and caused the vehicle to fail an inspection and maintenance tailpipe test.

What are the Possible Causes of the P0307 Code?

Since engine misfire is a very broad problem, there are many triggers that may cause this to happen. Here are some causes of an engine misfire:

  • A bad ignition coil, faulty spark plug wire, or failed spark plug wire.
  • A faulty fuel injector or problem with the injector’s circuit.
  • An internal engine problem, such as a leaking valve or worn camshaft lobe.

What are the Common Symptoms of the P0307 Code?

Keep in mind that although the P0307 code is a generic trouble code, it may present different symptoms depending on your vehicle’s year and make, and the exact cause of the misfire.

Here are the common symptoms associated with the P0307 code:

How to Diagnose the P0307 Code

As mentioned, a lot of factors can lead to engine misfires. It may sometimes be difficult to diagnose and determine what is really causing the fault. It is always the best option to bring your vehicle to an auto repair shop for proper diagnosis.

See also  P0300 Code: Random or Multiple Cylinder Misfire Detected

However, if you have the DIY repair skills to solve this problem yourself, here is a video you can watch to understand the code more:

How to Fix the P0307 Code

Diagnostic and repair procedures for an engine misfire in cylinder #7 may vary depending on your car’s year, make, and model. For example, repair steps for a P0307 in a Chevy may vary from a P0307 in a Ford.

Since there is no universal fix for this code, it is best to leave the job to a trusted professional, especially if you are not well-versed with engine repair. However, if you have the skills to fix this code yourself, you can use online auto repair sources and guides to identify what procedures are compatible with your vehicle. To help you with your repair works, you may also get an ALLDATA single-vehicle subscription.

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About The Authors
Richard McCuistian, ASE Certified Master Automobile Technician
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

CarParts Research Team
Written By Research Team

Automotive and Tech Writers

The Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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