Why is my car losing power?

Loss of engine power — particularly sudden or accompanied by the engine management light — often means the car has entered "limp mode," a protective state where the ECU limits power to prevent damage. This requires a diagnostic scan to read the fault code. Gradual power loss over time is often fuel, air, or exhaust related — clogged fuel filter, failing fuel pump, blocked DPF, or boost leak on turbocharged engines.

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Likely causes

Likely

Limp mode (ECU fault protection)

Sudden power cut often with EML — diagnostic scan needed to read the triggering fault code

Likely

Blocked DPF (diesel)

Severe DPF blockage prevents exhaust flow — major power loss on diesel vehicles

Possible

Turbo fault or boost leak

Whistling noise may accompany power loss on turbocharged engines

Possible

Clogged fuel filter

Restricts fuel delivery — worsens under high load

Possible

Catalytic converter blocked

Severe blockage restricts exhaust flow — feel the back pressure

Repairs you may need

Typical cost range: £40–£1200Diagnostic: £40–80. DPF clean: £80–200. Fuel filter: £50–150. Turbo: £500–1,500. Catalytic converter: £250–900.

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Related questions

This information is a general guide based on common causes of this symptom. Symptoms can have multiple causes and accurate diagnosis requires physical inspection by a qualified mechanic. Always consult a professional before deciding not to repair.