Your engine's computer has detected that cylinders are misfiring in a pattern that doesn't point to one specific cylinder — it's happening randomly across several of them. A misfire means one or more cylinders aren't burning fuel properly on every cycle, which wastes fuel and can damage the catalytic converter over time.
Symptoms
- Engine runs rough or shakes, especially at idle
- Noticeable loss of power or hesitation under acceleration
- Check engine light flashing (not just steady on) during the misfire
- A faint smell of unburned fuel from the exhaust
Likely causes
- Worn or fouled spark plugs — the single most common cause
- Vacuum leak letting unmetered air into the engine, leaning out multiple cylinders at once
- Fuel delivery problem — weak fuel pump or a clogged fuel filter starving several injectors
- Low or contaminated fuel, or a bad batch that's affecting the whole engine rather than one cylinder
How to diagnose it
- Pull the spark plugs and check their condition — worn, fouled, or badly gapped plugs across multiple cylinders confirm the likely cause
- Use a smoke test or spray carb cleaner around intake gaskets/hoses while the engine idles to spot a vacuum leak
- Check fuel pressure at the rail against the spec in the service manual — low pressure under load points to the fuel pump or filter
Typical fixes & cost
- Replace spark plugs (and ignition coils if worn) across all cylinders80–300 EUR
- Locate and repair a vacuum leak (hose, gasket, or intake boot)60–250 EUR
- Replace fuel filter, or fuel pump if pressure is confirmed low150–600 EUR
Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.
AS
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief