OBD Guide
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P1304

Cylinder 4 Misfiring Detected

P1304 is an OBD-II diagnostic trouble code meaning: Cylinder 4 Misfiring Detected. Common causes: faulty spark plugs, problems with the ignition coil. Estimated repair cost: $6–56.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$6–56 (est.)

Symptoms

  • The engine runs rough or shakes
  • Power Loss
  • Increased fuel consumption
  • Check Engine Light Is On
  • Popping sounds in the exhaust system

Causes

  • Faulty spark plugs
  • Problems with the ignition coil
  • Clogged fuel injectors
  • Low cylinder compression
  • Problems with sensors (mass air flow sensor, crankshaft position sensor)

How to Fix

  1. Check the condition of the spark plugs in cylinder 4
  2. Check ignition coil and wires
  3. Clean or replace fuel injector
  4. Check compression in cylinder
  5. Check the operation of engine sensors

Related codes

P0304P1300P1301

Error P1304 by Vehicle Brand

AcuraFordHondaInfinitiLincolnMercury

FAQ

What does the P1304 code mean?

P1304 is an OBD-II diagnostic trouble code that indicates: Cylinder 4 Misfiring Detected

What causes a P1304 error code?

The most common causes of P1304 include: Faulty spark plugs; Problems with the ignition coil; Clogged fuel injectors; Low cylinder compression.

How do I fix a P1304 diagnostic trouble code?

To fix P1304: Check the condition of the spark plugs in cylinder 4. Check ignition coil and wires. Clean or replace fuel injector. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1304?

Do not drive — repair immediately

How much does it cost to fix P1304?

The estimated repair cost for P1304 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

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