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P0305 Ford Code - Cylinder 5 Misfire Detected

Quick Answer

Misfire is defined as a lack of combustion in a cylinder due to the absence of a spark, incorrect fuel metering, low compression, or any other cause. Common causes include Faulty spark plug 5, Clogged or faulty fuel injector 5, Faulty ignition coil 5. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0305 Ford indicates Cylinder 5 Misfire Detected.
Common causes
Common causes include Faulty spark plug 5, Clogged or faulty fuel injector 5, Faulty ignition coil 5.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code Popularity 99,809
How popular is this code, among other codes? Medium
What is this?
Table of contents Created and updated by William Orellana on Apr 09, 2023
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Code P0305 Ford Description

Misfire is defined as a lack of combustion in a cylinder due to the absence of a spark, incorrect fuel metering, low compression, or any other cause.
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.
The Malfunction Indicator Lamp (MIL) blinks once per second when detecting a misfire severe enough to cause catalyst damage. If the MIL is in a 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.
This Diagnostic Trouble Code (DTC) sets when the misfire detection monitor detects an engine misfire in cylinder 5.
OBDII Code P0305 Ford - Cylinder 5 Misfire Detected - AutoCodes.com
P0305 Ford Code - Cylinder 5 Misfire Detected
What does this mean?

What are the Possible Causes of the DTC P0305 Ford?

  • Faulty spark plug 5
  • Clogged or faulty fuel injector 5
  • Faulty ignition coil 5
  • Fuel injector 5 harness is open or shorted
  • Fuel injector 5 circuit poor electrical connection
  • Ignition coil 5 harness is open or shorted
  • Ignition coil 5 circuit poor electrical connection
  • Insufficient cylinder 5 compression
  • Incorrect fuel pressure
  • Intake air leak

How to Fix the DTC P0305 Ford?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P0305 code means that cylinder #5 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder #5. If the problem persists more tests need to be done to diagnose the problem. See "Possible Causes" for the most common problems.

There is a Factory Service Bulletin for the 2011 Ford Mustang:
2011 Ford Mustang Factory Service Bulletin OBDII Code P0305
The Factory Service Bulletin recommends reprogramming the Powertrain Control Module (PCM) to resolve the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0305 Ford code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0305 Ford code?

Need more information on how to fix the P0305 Ford code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0305 Ford code diagnosed by a professional: Find a repair shop in your area

Information for Specific Ford Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0305 Ford Code

1. What are the common symptoms of OBDII code P0305 in a Ford, indicating a Cylinder 5 Misfire Detected?

- Common symptoms include rough idling, loss of power, engine vibration, poor fuel efficiency, and potential engine stalling.

2. What are some possible causes of a Cylinder 5 misfire in a Ford triggering OBDII code P0305?

- Potential causes may include faulty spark plugs or ignition coils, clogged fuel injectors, vacuum leaks, low compression in the cylinder, or issues with the fuel system.

3. How can I diagnose the root cause of a Cylinder 5 misfire triggering code P0305 in my Ford?

- Diagnosis typically involves checking spark plugs, ignition coils, fuel injectors, compression levels, and conducting a thorough inspection of the ignition and fuel systems.

4. Is it safe to continue driving my Ford with OBDII code P0305 related to a Cylinder 5 misfire?

- It is not recommended to drive the vehicle with a misfire, as it can lead to further damage to the engine or catalytic converter. Prompt diagnosis and repair are advised.

5. Can a dirty or clogged fuel injector cause a Cylinder 5 misfire triggering code P0305 in a Ford?

- Yes, a dirty or clogged fuel injector can disrupt the fuel delivery to the cylinder, resulting in a misfire and triggering the OBDII code P0305.

6. What are some basic repair tips for addressing a Cylinder 5 misfire in a Ford associated with OBDII code P0305?

- Repair tips may include replacing spark plugs, ignition coils, or fuel injectors, performing a fuel system cleaning, checking for vacuum leaks, and ensuring proper engine compression.

7. Will resetting the OBDII code P0305 related to a Cylinder 5 misfire in my Ford make the issue go away?

- Resetting the code will clear the check engine light temporarily, but it will not fix the underlying problem causing the misfire. Proper diagnosis and repair are necessary.

8. Can a faulty ignition coil be a common cause of a Cylinder 5 misfire leading to the OBDII code P0305 in a Ford?

- Yes, a faulty ignition coil can cause a misfire in a specific cylinder, such as Cylinder 5, triggering the OBDII code P0305 in a Ford.

9. How crucial is it to address a Cylinder 5 misfire triggering code P0305 in a Ford promptly?

- It is essential to address the issue promptly to prevent further engine damage, poor performance, and potential catalytic converter damage, which can be costly to repair.

10. Are there any preventive maintenance measures to reduce the risk of encountering a Cylinder 5 misfire with code P0305 in a Ford?

- Regular maintenance, such as timely spark plug replacements, using high-quality fuel, and ensuring proper engine tune-ups, can help prevent Cylinder 5 misfires and related issues in a Ford.

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