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P0302 Mercury Code - Cylinder 2 Misfire Detected

Quick Answer

When the diagnostic code P0302 Mercury appears, it indicates that a misfire has been detected in cylinder 2 of the engine. Common causes include Faulty spark plug in cylinder 2, Failing ignition coil specific to cylinder 2, Clogged fuel injector for cylinder 2. 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
P0302 Mercury indicates Cylinder 2 Misfire Detected.
Common causes
Common causes include Faulty spark plug in cylinder 2, Failing ignition coil specific to cylinder 2, Clogged fuel injector for cylinder 2.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 06, 2024
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Code P0302 Mercury Description

When the diagnostic code P0302 Mercury appears, it indicates that a misfire has been detected in cylinder 2 of the engine. A misfire occurs when the air-fuel mixture in the combustion chamber fails to ignite at the proper time, leading to a disruption in the engine's normal operation. This can result in a range of issues, including reduced engine performance, increased fuel consumption, and potential damage to the catalytic converter.

OBDII Code P0302 Mercury - Cylinder 2 Misfire Detected
P0302 Mercury Code - Cylinder 2 Misfire Detected

Common Causes of P0302 Mercury

  1. Faulty spark plug in cylinder 2
  2. Failing ignition coil specific to cylinder 2
  3. Clogged fuel injector for cylinder 2
  4. Vacuum leaks near cylinder 2
  5. Low compression in cylinder 2

Symptoms of P0302 Mercury

  1. Rough idle or shaking engine
  2. Loss of power or acceleration
  3. Increased fuel consumption
  4. Engine hesitation or stalling
  5. Illuminated check engine light

How to Fix P0302 Mercury

  1. Diagnose the issue by performing a compression test, checking spark plugs, ignition coils, and fuel injectors.
  2. Replace the spark plug in cylinder 2 if it is found to be faulty.
  3. Test and replace the ignition coil for cylinder 2 if necessary.
  4. Clean or replace the fuel injector for cylinder 2 if it is clogged.
  5. Address any vacuum leaks near cylinder 2 by inspecting and repairing any damaged hoses or connections.

Cost to Fix P0302 Mercury

The cost of repairing a cylinder 2 misfire can vary depending on the specific cause of the issue and the parts needed for repair. Typically, the cost for parts such as spark plugs, ignition coils, or fuel injectors can range from $50 to $200 per component. Labor costs can add an additional $100 to $300, depending on the shop's hourly rates and the complexity of the repair. Overall, the total cost for addressing a P0302 code in a Mercury vehicle may fall between $150 and $500. It's recommended to consult with a qualified mechanic or auto repair shop for a more accurate estimate based on the specific circumstances.

What does this mean?

Tech Notes for P0302 Mercury

The P0302 code means that cylinder #2 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 #2. If the problem persists more tests need to be done to diagnose the problem. See "Possible Causes" for the most common problems.

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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 P0302 Mercury Code

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  • i am an ASE Certified Tech, but i have a 2008 merc, sable, gives code po302 which is #2 cylinder misfire, had to pull plentim off so i replaced 1,2,3 coil packs and all plugs.no change, so i replaced #2 injector, still no change, should i go to PCM or crank sensor?

    Reply to Comment

  • Unfortunately never had that problem before, the only similar issue I had was with a bad fuel injector wire. The wire protector was still OK, but the wire inside was broken. My suggestion is to check continuity between the PCM and fuel injector and ignition coil.

    Reply to Comment