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P0303

Cylinder 3 Misfire Detected

Fix Cost
$20 - $300
Parts & Labor
Difficulty
2/5
Medium
30 mins - 2 hours
DIY Possible?
✅ Yes
Save money
Category
Powertrain
System

📖 What Does P0303 Mean?

The engine control module has detected a misfire specifically in cylinder 3. This means the air/fuel mixture in cylinder 3 is not igniting properly.
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Symptoms

  • Rough idle
  • engine shaking
  • loss of power
  • flashing check engine light during acceleration
  • poor fuel economy.
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Common Causes

  • Faulty spark plug in cylinder 3
  • bad ignition coil
  • clogged fuel injector
  • low compression
  • carbon buildup
  • vacuum leak affecting cylinder 3.
Fix Guide
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Possible Solutions

Replace spark plug for cylinder 3, swap ignition coil with another cylinder to test, clean fuel injector, perform compression test, remove carbon deposits.

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Common Questions About P0303

Q

Can I drive with code P0303?

A

No, it is not recommended. Seeing code P0303 indicates a serious issue that could damage your engine or transmission if ignored. You should stop driving and have it inspected immediately.

Q

How much does it cost to fix P0303?

A

The estimated repair cost for code P0303 is between $20 and $300. This includes parts and labor for most makes and models.

Q

Is this code easy to fix myself?

A

Yes, this is often a DIY-friendly repair. With basic tools and the correct part, many owners can resolve this themselves in under an hour.

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Related Diagnostic Codes

Other codes that may appear with P0303

💡 Why These Codes Are Related:

  • Similar Issues: Same root cause or component failure
  • Related Problems: Often occur together due to system interactions
  • Sequential Codes: Progressive failure stages or multiple sensors
  • Same System: Components within the same automotive system