Engine Misfire: Causes, Symptoms and Fixes
A misfire happens when one or more cylinders fail to burn fuel properly. The engine shakes, loses power and the check-engine light may flash.
Common symptoms
Rough idle, jerking when accelerating, poor fuel economy, a petrol smell from the exhaust and a flashing check-engine light.
Main causes
Ignition: worn spark plugs, weak ignition coils or damaged plug leads. Fuel: blocked or leaking injectors, weak fuel pump or dirty fuel. Air: vacuum leaks or a dirty throttle body. Mechanical: low compression from worn rings, valves or a head gasket. Electrical: faulty crankshaft or camshaft sensors and wiring faults.
How diagnosis works
A scanner shows which cylinder misfires (for example P0302 is cylinder 2). The mechanic then swaps or tests the coil and plug, checks injectors, measures compression and inspects the wiring to that cylinder.
Is it safe to drive?
A flashing check-engine light means unburnt fuel is reaching the catalytic converter and can damage it. Drive only a short distance, gently, to a workshop.
Prevention
Replace spark plugs on schedule, use clean fuel, change air filters and fix warning lights early.
We clear misfires in Mbale every week. Contact us to book a diagnosis.