AutoCodes – Pontiac – P0304 Pontiac

P0304 Pontiac Code - Cylinder 4 Misfire Detected

Quick Answer

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. 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 Pontiac indicates Cylinder 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 27,342

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 Aug 09, 2022

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

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. The Engine Control Module (ECM) can detect these variations by closely monitoring the crankshaft position sensor signal. The signals of the camshaft position sensors are used to determine which cylinder is misfiring. If the ECM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, the Diagnostic Trouble Code (DTC) will be set. Under certain driving conditions, a misfire rate can be high enough to cause the catalytic converter to overheat, damaging the converter. The Malfunction Indicator Lamp (MIL) flashes when the converter is overheating, damaging conditions are present, and the DTC is set. The DTC will be set when the ECM detects a crankshaft rotation speed variation indicating a single-cylinder misfire rate sufficient to cause emissions levels to exceed mandated standards.

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

What does this mean?

What are the Possible Causes of the DTC P0304 Pontiac?

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 Pontiac?

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 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 need to be done to diagnose the problem, see "Possible Causes".

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0304 Pontiac 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.

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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 Pontiac Code

1. What are common symptoms of OBDII code P0304 on a Pontiac indicating Cylinder 4 misfire?

- Common symptoms include rough idle, loss of power, engine misfires, and potentially increased fuel consumption.

2. What are the possible causes of a Cylinder 4 misfire detected in a Pontiac triggering code P0304?

- Causes may include faulty spark plugs, damaged ignition coils, clogged fuel injectors, vacuum leaks, or low compression in the cylinder.

3. How can I diagnose the specific cause of the Cylinder 4 misfire in my Pontiac with code P0304?

- You can diagnose the issue by performing tests such as inspecting spark plugs, checking ignition coils, conducting a compression test, and using a scan tool to monitor engine data.

4. What are some repair tips for addressing OBDII code P0304 related to a Cylinder 4 misfire on a Pontiac?

- Repair tips may involve replacing spark plugs, ignition coils, or fuel injectors, cleaning or replacing air filters, checking for vacuum leaks, and ensuring proper engine compression.

5. Can driving with OBDII code P0304 related to a Cylinder 4 misfire in a Pontiac cause further damage?

- Continuing to drive with a Cylinder 4 misfire can potentially cause damage to the catalytic converter, oxygen sensors, or other engine components over time if left unresolved.

6. How important is it to address OBDII code P0304 indicating a Cylinder 4 misfire on a Pontiac promptly?

- It is crucial to address the issue promptly to prevent potential damage to the engine, ensure optimal performance, and avoid more costly repairs down the line.

7. Are there any preventative measures to help avoid OBDII code P0304 related to a Cylinder 4 misfire in a Pontiac?

- Regular maintenance such as changing spark plugs, inspecting ignition components, using quality fuel, and addressing engine issues promptly can help prevent Cylinder 4 misfires.

8. Is it possible to reset the OBDII code P0304 for a Cylinder 4 misfire on a Pontiac without addressing the underlying issue?

- While you can clear the code temporarily, it is not recommended as the underlying problem causing the misfire will persist and may lead to further issues if left unresolved.

9. Can extreme weather conditions or driving habits contribute to triggering OBDII code P0304 for a Cylinder 4 misfire in a Pontiac?

- Yes, extreme weather conditions, such as very cold temperatures, or aggressive driving habits can potentially contribute to the occurrence of Cylinder 4 misfires and trigger code P0304.

10. How can a professional mechanic help diagnose and repair OBDII code P0304 linked to a Cylinder 4 misfire in a Pontiac?

- A professional mechanic can use specialized tools and expertise to accurately diagnose the issue, perform necessary repairs or replacements, and ensure the problem is resolved effectively.