Why doesn't my 4-cylinder car have a cylinder 5?

P0305 only applies to engines with six or more cylinders. If you have a 4-cylinder engine, P0305 isn't a possible code. The cylinder-specific codes for a 4-cylinder are P0301 through P0304 only.

Where is cylinder 5 on my engine?

On an inline-6, cylinder 5 is the fifth cylinder from the front. On a V6, cylinder 5 is often a middle position on Bank 2. On a V8, the position depends on the manufacturer's numbering convention — check the engine service information for your specific engine.

Is P0305 less serious than P0301 because there are more cylinders?

The engine will run rougher with fewer cylinders missing, but the underlying risk to the catalytic converter is the same. A misfire that goes unaddressed will damage the catalyst regardless of how many cylinders the engine has.

How much does P0305 cost to fix?

Most fixes land between $50 and $400 — a single plug, coil, or injector cleaning. On V engines where cylinder 5 is on the rear bank, removing the intake plenum can add an hour or two of labor. Compression-related repairs start at $1,000.

OBD-II trouble code

P0305: Cylinder 5 Misfire Detected

The engine computer detected a misfire specifically in cylinder 5. This code only applies to engines with six or more cylinders. Diagnosis is more targeted than P0300 — the bad part is on or feeding cylinder 5.

Quick facts

System: Powertrain
Category: Ignition and Misfire
Severity: High severity
Drivable: Usually safe to drive short-term
Repair cost range: $50 – $1,500
DIY difficulty: Intermediate DIY

What does P0305 mean?

A misfire is a cylinder that fails to combust properly. The engine control module (ECM) detects misfires by monitoring crankshaft speed — a healthy combustion event accelerates the crankshaft slightly, and the ECM watches for the missing acceleration that signals a failed combustion event. When the ECM isolates the misfire to a single cylinder, it sets a cylinder-specific code instead of the generic P0300.

P0305 means the misfire is in cylinder 5. This code only applies to engines with six or more cylinders — inline-6, V6, V8, V10, and V12 configurations. On an inline-6, cylinder 5 is the fifth cylinder from the front. On a V6 in many configurations, cylinder 5 is the middle cylinder on Bank 2. On a V8, the position depends on the manufacturer — Ford and GM use different numbering schemes. Check your engine's service information for the exact location.

A flashing check engine light during P0305 indicates the misfire is active. Unburned fuel reaches the catalytic converter and can damage it quickly. Pull over safely if the light is flashing. If the light is steady, drive directly to a shop and avoid hard acceleration.

Common causes

Worn or fouled spark plug in cylinder 5
Failing ignition coil for cylinder 5 (most common on coil-on-plug engines)
Faulty fuel injector for cylinder 5 (stuck, clogged, or leaking)
Low compression in cylinder 5 from a burned valve, worn rings, or head gasket leak
Cracked or damaged spark plug wire feeding cylinder 5 (older engines)
Carbon buildup on the intake valve for cylinder 5
Vacuum leak isolated to the cylinder 5 intake runner
Wrong-gap or improperly installed spark plug

Symptoms

Check engine light on or flashing
Rough idle and engine shaking
Loss of power on acceleration
Hesitation or stumble
Poor fuel economy
Smell of unburned fuel from the exhaust
Less noticeable than a 4-cylinder misfire — the engine still runs on 5 of 6 (or 7 of 8) cylinders

Diagnostic steps

1.Confirm the code is P0305 alone — companion misfire codes on the same bank may indicate a broader issue.
2.Inspect the spark plug in cylinder 5. Compare condition to the other plugs.
3.Swap the ignition coil from cylinder 5 with a known-good coil from another cylinder. Clear the code and drive. If the misfire moves with the swapped coil, the coil is bad.
4.Repeat with the spark plug.
5.Test the cylinder 5 fuel injector resistance and confirm pulsing.
6.If ignition and fuel test fine, perform a compression test on cylinder 5.

Repair cost

$50 – $1,500

Single spark plug $10 to $30 plus 15 to 30 minutes of labor. Ignition coil $40 to $200 plus brief labor. Fuel injector $100 to $400 plus 1 to 3 hours. On V engines, cylinder 5 may be on the rear bank, which can require removing the intake plenum and add an hour or two of labor. Compression-related repairs run $1,000 and up.

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DIY vs shop

This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.