AutoCodes – Isuzu – P0304 Isuzu

P0304 Isuzu Code - Cylinder Number 4 Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Faulty Spark Plug #4, Clogged or faulty Fuel Injector #4, Faulty Ignition Coil #4. 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: P0304 Isuzu indicates Cylinder Number 4 Misfire Detected.
Common causes: Common causes include Faulty Spark Plug #4, Clogged or faulty Fuel Injector #4, Faulty Ignition Coil #4.
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 18,378

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0304 Isuzu Description

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.

OBDII Code P0304 Isuzu - Cylinder Number 4 Misfire Detected - AutoCodes.com — P0304 Isuzu Code - Cylinder Number 4 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0304 Isuzu?

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

How to Fix the DTC P0304 Isuzu?

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 P0304 code means that the cylinder 4 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 4. If the problem persists more tests needs to be done to diagnose problem, see "Possible Causes"

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0304 Isuzu 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 P0304 Isuzu code?

Need more information on how to fix the P0304 Isuzu code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P0304 Isuzu Code

1. What are the common symptoms of an OBDII code P0304 Isuzu (Cylinder Number 4 Misfire Detected)?

- Common symptoms include engine misfiring, rough idling, loss of power, and increased fuel consumption.

2. What are the possible causes of the P0304 Isuzu trouble code?

- Potential causes include faulty spark plugs, a malfunctioning ignition coil, clogged fuel injector, vacuum leaks, or low compression in cylinder number 4.

3. How can I diagnose the root cause of the Cylinder Number 4 misfire in my Isuzu?

- Diagnosis typically involves inspecting spark plugs, ignition coils, fuel injectors, and performing a compression test on cylinder number 4.

4. Can a clogged fuel injector trigger the P0304 trouble code in an Isuzu?

- Yes, a clogged or malfunctioning fuel injector can lead to inadequate fuel delivery to cylinder number 4, resulting in a misfire detected by the OBDII system.

5. Are there any simple repair tips for addressing a P0304 Isuzu code?

- Basic repair tips include replacing spark plugs, checking ignition coils, cleaning or replacing fuel injectors, and ensuring there are no vacuum leaks in the system.

6. How important is it to address a P0304 Isuzu code promptly?

- It is crucial to address the code promptly to prevent potential engine damage, further fuel inefficiency, and to maintain optimal vehicle performance.

7. Can low engine compression in cylinder number 4 trigger the P0304 trouble code?

- Yes, low compression can cause a misfire in cylinder number 4, leading to the detection of the P0304 Isuzu trouble code by the OBDII system.

8. Is it safe to continue driving my Isuzu with a P0304 trouble code?

- It is not recommended to drive the vehicle with a P0304 code as it can lead to further damage to the engine and may cause safety hazards on the road.

9. How can I reset the OBDII code P0304 in my Isuzu after addressing the underlying issue?

- The code can be reset using an OBDII scanner or by disconnecting the car's battery for a few minutes to clear the error code.

10. Can a P0304 Isuzu trouble code be intermittent or occur only under specific conditions?

- Yes, the misfire detected in cylinder number 4 triggering the P0304 code can sometimes be intermittent and may occur only under specific driving conditions.