Volkswagen P0304

Cylinder 4 misfire on VW — TSI coil pack failure very common; TDI injector or glow plug; older PD diesels injector loom.

Volkswagen P0304 — Cylinder 4 misfire on VW — TSI coil pack failure very common; TDI injector or glow plug; older PD diesels injector loom. Typical UK independent garage cost: £100–£580.

What actually causes P0304 on a Volkswagen

VW TSI coil packs (Bosch/Eldor) are the #1 cause of P0304 on petrol Mk5/6/7 Golfs — fail in pairs typically by 60k–80k miles. Cyl 4 (rearmost) goes first because heat is highest. On 1.6/2.0 TDI CR engines cyl 4 misfire is usually a failed injector or glow plug. Always pull plugs to check for oil/carbon before assuming coil.

Volkswagen engines that log P0304

• 1.4/1.8/2.0 TSI (Golf, Passat, Tiguan, Polo)
• 1.6/2.0 TDI CR (Golf, Passat, Caddy, Tiguan)
• 1.9 TDI PD (older Golf, Passat, Bora)

How we diagnose P0304 on a Volkswagen

1. VCDS — read misfire counters per cylinder
2. Swap coil 4 with coil 1, retest to confirm
3. Pull spark plug — replace if worn or fouled
4. On TDI, glow plug test and injector smooth-running values
5. Replace component, clear codes

The common misdiagnosis to avoid

VW dealers will quote a complete coil set on a TSI with one misfire (£280+) — swap the bad cyl 4 coil with cyl 1 first, replace only what's actually failed, save the customer 70%.

Volkswagen P0304 repair cost in the UK

Expect £100–£580 including parts and labour at an independent garage. Main-dealer quotes on Volkswagen are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.

Bob's workshop tip

On Mk5/6 Golf TSI with one failed coil, recommend doing all 4 plugs and ONLY the failed coil — the other coils will fail eventually but customer prefers an honest 'when' answer to being upsold all 4 now.

Codes usually seen alongside P0304 on Volkswagen

• P0300
• P0301
• P0302
• P0303

Symptoms drivers report with P0304

• Engine warning light flashing (not steady) under load
• Noticeable juddering at idle in gear
• Smell of unburnt fuel from the exhaust
• Misfire worse when engine is cold and damp
• Significantly reduced power

Repairs that clear P0304

• Plug & coil replacement

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0304 guide.