The OBD code P0304 for Ford indicates a misfire in cylinder 4. This affects the engine’s performance, causing symptoms like engine light on, lack of power, hard starting, and engine hesitation.
Common causes include a faulty spark plug, clogged fuel injector, or ignition coil issues.
While not an immediate danger, it can lead to further engine damage if left unresolved.
A possible fix involves inspecting and repairing the components related to cylinder 4.
Repair Importance Level | 10.0 (Out of 10) |
Estimated Repair Time | Approximately 1.0 hour |
Repair Difficulty Level | 10.0 (Out of 10) |
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Symptoms of the Ford p0304 OBD Code
Engine misfires on cylinder 4 in Ford vehicles with fault code P0304.
- With Ford OBD code P0304, the Engine Light will be ON.
- Lack/loss of power may be experienced.
- Hard start can occur.
- Engine hesitation might be noticeable.
Causes of the Ford p0304 OBD Code
Possible reasons for Ford code P0304 include ignition system faults and fuel delivery issues.
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- P0304 can be caused by Faulty Spark Plug #4.
- Clogged or faulty Fuel Injector #4.
- Faulty Ignition Coil #4.
- Fuel Injector #4 harness is open or shorted.
- Fuel Injector #4 circuit poor electrical connection.
- Ignition Coil #4 harness is open or shorted.
- Ignition Coil #4 circuit poor electrical connection.
- Insufficient cylinder 4 compression.
- Incorrect fuel pressure.
- Intake air leak.
Fixing Ford Error Code p0304 Step By Step
Address the misfire on cylinder 4 in a Ford vehicle by checking spark plugs and ignition components.
- To fix a Ford OBDII code P0304, start by reviewing the possible causes related to cylinder 4 misfire.
- Visually inspect the ignition system components such as spark plugs, ignition coils, and spark plug wires for any signs of wear or damage.
- Check the fuel injector for proper operation and ensure it is delivering fuel correctly to cylinder 4.
- Verify the compression in cylinder 4 to rule out any internal engine issues causing the misfire.
- If all components check out, consider swapping the ignition coil or fuel injector with another cylinder to see if the misfire follows.
- Finally, clear the fault code and test drive the vehicle to confirm the repair.
Cost Of Fixing Ford p0304 Fault Code
Diagnosing and repairing Ford code P0304 typically involves addressing cylinder 4 misfire issues.
The cost to diagnose and fix a Ford OBD code P0304 typically ranges from $75 to $150, with an estimated repair time of 1. 0 hour.
The total cost depends on labor rates, shop fees, and any additional parts or services needed to address the misfire issue in cylinder 4.
Details of the Ford p0304 OBD Code
Ford code P0304 indicates a misfire in cylinder 4 of the engine.
Code P0304 means a misfire was detected in cylinder 4. It’s triggered by the Engine Control Module (ECM) based on crankshaft speed fluctuations.
This code indicates that cylinder 4 is not contributing properly to the engine’s combustion cycle, leading to a rough running engine and potential power loss.
Misfires can be caused by issues such as faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, or low compression in the cylinder.
Mechanic’s Tech Notes
For Ford code P0304, cylinder 4 misfire detected.
To diagnose and fix OBDII code P0304 on a Ford, focus on cylinder 4 misfire.
Use a scan tool to monitor live misfire data and pinpoint the issue.
Check spark plug condition, ignition coil operation, and fuel injector performance for cylinder 4. Use a voltmeter to test the coil’s primary and secondary circuits for proper voltage and resistance.
Inspect the wiring harness and connectors for any damage or corrosion.
Clear the code after repairs and test drive to confirm the issue is resolved.
FAQ
Common causes of OBD code P0304 in a Ford vehicle include faulty Spark Plug #4, clogged Fuel Injector #4, faulty Ignition Coil #4, and poor electrical connections.
Diagnose P0304 misfire in Ford: Check spark plug, fuel injector, ignition coil #4. Inspect wiring for damage, connector pins for issues.
It is not safe to continue driving with OBD code P0304 on a Ford. Address the causes listed, focusing on Spark Plug #4, Fuel Injector #4, and Ignition Coil #4.

Wrap Up
If your Ford is running rough and the check engine light is on with OBD code P0304, it indicates a misfire in cylinder 4. Possible causes include a faulty spark plug, ignition coil, fuel injector, or low compression in that cylinder.
To address Ford OBD code P0304, start by inspecting the spark plug, ignition coil, and fuel injector for cylinder 4. Check for any signs of damage or wear.
Perform a compression test to ensure the engine’s internal condition is healthy.
If necessary, replace the faulty component to resolve the misfire issue.