P0302 high Severity

P0302: Cylinder 2 Misfire Detected

Engine performance may be reduced with rough idle, hesitation, loss of power and increased emissions; a flashing check engine light indicates a severe misfire requiring immediate attention.

Overview

OBD2 P0302 indicates the powertrain control module has detected a misfire specifically in cylinder #2 due to ignition, fuel delivery, mechanical or sensor issues.

Common Symptoms

  • Check Engine Light illuminated
  • Rough or erratic idle
  • Loss of power or hesitation during acceleration
  • Decreased fuel economy
  • Engine vibration or shaking
  • Occasional stalling

Most Common Causes

Faulty spark plug in cylinder 2 high

Spark plugs that are worn, fouled or damaged frequently fail to ignite the air‑fuel mixture correctly.

Failed ignition coil on cylinder 2 high

Ignition coils that are weak or intermittent can prevent sufficient spark, causing misfires.

Clogged or faulty fuel injector on cylinder 2 medium

Fuel delivery issues specific to cylinder 2 can disrupt the correct fuel mixture needed for combustion.

Vacuum leak affecting cylinder 2 medium

Unmetered air entering near cylinder 2 can create a lean condition and misfire.

Low compression in cylinder 2 medium

Mechanical issues such as worn piston rings, valve problems or head gasket leaks can reduce compression.

Sensor issues or timing problems low

Crankshaft/camshaft position sensor faults or incorrect timing can contribute to misfire detection.

Diagnostic Steps

  1. Use an OBD‑II scan tool to verify P0302 and check for related codes.
    Expected: P0302 code present; potential accompanying codes indicating related systems.
    Interpretation: Confirms cylinder 2 misfire and provides context for further diagnostics.
  2. Inspect and test spark plug and ignition coil for cylinder 2.
    Expected: Worn plug, damaged coil or irregular spark.
    Interpretation: If defective, these are common root causes and replacement may resolve misfire.
  3. Perform swap test by moving cylinder 2 ignition coil to another cylinder.
    Expected: If misfire moves to another code (e.g., P0301), coil is faulty.
    Interpretation: Helps isolate coil vs other issues.
  4. Check fuel injector operation on cylinder 2 (balance test or resistance check).
    Expected: Proper injector click and correct resistance values.
    Interpretation: Clogged or faulty injector can cause misfire.
  5. Inspect for vacuum leaks near intake manifold and cylinder 2.
    Expected: Smoke or carb cleaner test reveals leaks.
    Interpretation: Leaks can cause lean conditions leading to misfires.
  6. Perform compression test on all cylinders.
    Expected: Cylinder 2 compression within specification and consistent with others.
    Interpretation: Low or inconsistent compression suggests mechanical fault.

Repair Solutions

Replace spark plug on cylinder 2 easy
Estimated Cost: $15 - $100

One of the most common and cost‑effective fixes for persistent misfires.

Replace ignition coil for cylinder 2 easy
Estimated Cost: $50 - $300

Often resolves misfire if the coil is weak or intermittent.

Clean or replace fuel injector for cylinder 2 medium
Estimated Cost: $100 - $500

Required if injector is clogged or malfunctioning.

Repair vacuum leaks or intake manifold issues medium
Estimated Cost: $50 - $300

Resolving air leaks can restore correct air‑fuel ratio.

Address mechanical engine issues (e.g., compression repair) hard
Estimated Cost: $300 - $1500

Major mechanical repairs depend on root cause and can be costly.

Common Misdiagnoses

Avoid these common diagnostic mistakes:

  • Assuming a P0302 code always indicates ignition coil failure without testing other systems
  • Replacing multiple expensive components without checking fuel delivery or vacuum leaks first

Frequently Asked Questions

Technical definition of P0302 OBD-II Code

Cylinder 2 Misfire Detected is the standard definition for P0302. This diagnostic code is triggered when the ECU detects a problem in the Ignition.

Reflecting on severity: How bad is P0302?

This is a high priority issue. Engine performance may be reduced with rough idle, hesitation, loss of power and increased emissions; a flashing check engine light indicates a severe misfire requiring immediate attention.

What happens when the P0302 code is active?

Drivers often report: Check Engine Light illuminated, Rough or erratic idle, Loss of power or hesitation during acceleration when this code is present.

Common triggers for the P0302 error

Potential culprits include: Faulty spark plug in cylinder 2, Failed ignition coil on cylinder 2, Clogged or faulty fuel injector on cylinder 2. A proper diagnosis is recommended.

Repair cost breakdown for P0302

It depends on what needs to be fixed. Replace spark plug on cylinder 2 repairs are cheaper (~$100), while Address mechanical engine issues (e.g., compression repair) repairs are on the higher end (~$1500).

Does P0302 affect Ford, Toyota, or Honda?

Yes, P0302 is a generic code that applies to all OBD-II compliant vehicles, including Ford, Toyota, Honda, Chevrolet, Nissan, Dodge, BMW, and more.

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