All Codes/P0304

Code P0304Immediate

Cylinder 4 Misfire Detected

Cylinder #4 isn't firing - your engine is running unbalanced, causing shaking and power loss.

Professional Service
Available
Category
ignition
Common In
Lexus ES350

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Immediate Action Required

This issue can cause significant damage if ignored. Stop driving if experiencing severe symptoms.

Recommended Actions:

  • Pull over safely if engine is misfiring badly
  • Call for professional diagnosis immediately
  • Do not ignore flashing check engine light
  • Avoid highway driving until repaired

What This Code Means

The #4 cylinder is not firing properly, affecting engine performance.

"Cylinder #4 isn't firing - your engine is running unbalanced, causing shaking and power loss."

Common Causes

1

Failed spark plug cylinder 4

2

Bad ignition coil cylinder 4

3

Fuel injector failure cylinder 4

4

Valve problems cylinder 4

5

Head gasket leak affecting cylinder 4

Symptoms You May Notice

Noticeable shaking
Power loss
Rough running
Check engine light flashing
Poor acceleration

Professional Diagnostic Steps

Our technicians will perform these checks:

Inspect spark plug condition
Test coil pack operation
Verify injector spray pattern
Leak-down test cylinder 4

Commonly Affects These Vehicles

Lexus ES350
Acura MDX
Buick Enclave
Cadillac CTS
Genesis G70

Note: This code can appear in any vehicle. These are just the most common.

Repair Cost Breakdown

DiagnosisAvailable
Often waived with repair
PartsQuality Options
OEM or quality aftermarket
LaborProfessional Service
Professional installation
Total RangeCall for Quote

Why Choose Us?

  • ASE Certified Technicians
  • Latest Diagnostic Equipment
  • Warranty on All Repairs
  • Upfront, Honest Pricing
  • Same Day Service Available

Frequently Asked Questions About Code P0304

Can I keep driving with code P0304?

Avoid driving except to repair shop - protect your catalytic converter

How much will it cost to fix P0304?

The repair approach depends on the specific cause and your vehicle.The most common cause (failed spark plug cylinder 4) usually costs on the lower end of this range.

Will code P0304 clear itself?

While the check engine light may turn off if the condition improves temporarily, the code will remain stored in your vehicle's computer. The underlying issue still needs to be addressed to prevent the code from returning and potentially causing damage.

Is P0304 covered under warranty?

Coverage depends on your vehicle's warranty status and the specific component that failed. Extended warranties may cover this repair.

Don't Guess - Get Professional Diagnosis

Code P0304 can have multiple causes. Our diagnostic process ensures we fix the right problem the first time.