AutoCodes – Honda – P0304 1997 Honda Civic

P0304 1997 Honda Civic Code - Cylinder Number 4 Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Valve adjustment, Faulty Spark Plug #4, Clogged or faulty Fuel Injector #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 1997 Honda Civic indicates Cylinder Number 4 Misfire Detected.
Common causes: Common causes include Valve adjustment, Faulty Spark Plug #4, Clogged or faulty Fuel Injector #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 6,262

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 Apr 09, 2019

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0304 1997 Honda Civic 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 1997 Honda Civic - Cylinder Number 4 Misfire Detected - AutoCodes.com — P0304 1997 Honda Civic Code - Cylinder Number 4 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0304 1997 Honda Civic?

Valve adjustment
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 1997 Honda Civic?

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 1997 Honda Civic 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 1997 Honda Civic code?

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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 1997 Honda Civic Code

1. What are the common symptoms of OBDII code P0304 in a 1997 Honda Civic?

Symptoms may include engine misfires, rough idling, loss of power, decreased fuel efficiency, and in some cases, the Check Engine light may illuminate.

2. What are the possible causes of a cylinder number 4 misfire in a 1997 Honda Civic?

Common causes include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression in the cylinder, or a problem with the engine's computer.

3. How can I diagnose the source of the misfire in cylinder number 4 of my 1997 Honda Civic?

Diagnosis typically involves checking the spark plug, ignition coil, fuel injector, compression in the cylinder, and performing a scan tool test to pinpoint the exact cause.

4. Can driving with a cylinder number 4 misfire in a 1997 Honda Civic cause further damage?

Continued driving with a misfire can potentially damage the catalytic converter over time, leading to more costly repairs. It's advisable to address the issue promptly.

5. What are some DIY repair tips for addressing a cylinder number 4 misfire in a 1997 Honda Civic?

DIY repair tips include checking and replacing spark plugs, inspecting ignition coils and fuel injectors, ensuring proper fuel and air flow, and addressing any vacuum leaks.

6. How much does it typically cost to repair a cylinder number 4 misfire in a 1997 Honda Civic?

The cost of repair can vary depending on the exact cause of the misfire and whether you choose to DIY or seek professional help. Costs may range from $100 for simple fixes to several hundred dollars for more complex issues.

7. Is it safe to drive my 1997 Honda Civic with a cylinder number 4 misfire?

It is generally not recommended to drive with a misfire, as it can lead to further damage and potentially compromise the vehicle's performance and fuel efficiency. It's best to address the issue promptly.

8. How often should I replace spark plugs in a 1997 Honda Civic to prevent cylinder misfires?

It is recommended to replace spark plugs every 30,000 to 50,000 miles in a 1997 Honda Civic to maintain optimal engine performance and prevent misfires.

9. Can a cylinder number 4 misfire in a 1997 Honda Civic be caused by a clogged fuel injector?

Yes, a clogged or malfunctioning fuel injector can cause a misfire in cylinder number 4. Cleaning or replacing the fuel injector may resolve the issue.

10. Will resetting the Check Engine light resolve the cylinder number 4 misfire in my 1997 Honda Civic?

Resetting the Check Engine light will not fix the underlying issue causing the misfire. It's important to diagnose and address the root cause of the problem to prevent further issues.