Ignition coil failure. Spark plug wear or gap issue. Injector fault. Low cylinder compression. Intake manifold gasket leak near cylinder 4.

Which cars are affected by P0304?

P0304 is most commonly reported on BMW, Ford, Volkswagen, Vauxhall, Mercedes-Benz vehicles, but can appear on any make.

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P0304

High severity

Cylinder 4 Misfire Detected

Cylinder 4 is misfiring. The crankshaft position sensor has detected a variation in engine speed that isolates the problem to this specific cylinder.

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Common causes of P0304

1Ignition coil failure

2Spark plug wear or gap issue

3Injector fault

+2 more causes

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Commonly affected vehicles

BMWFordVolkswagenVauxhallMercedes-Benz

P0304 can appear on any vehicle — these are the makes where it is most frequently reported.

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Related fault codes

P0171Medium

System Too Lean (Bank 1)

P0300High

Random/Multiple Cylinder Misfire Detected

P0420Medium

Catalyst System Efficiency Below Threshold (Bank 1)

P0172Medium

System Too Rich (Bank 1)