After I filled up with petrol about 600 meter my engin light came on for a second and the ford focus st engin start shaking dit a test there is a misfire on piston one what can be wrong
Check the fuel first, make sure it is gasoline and not water or diesel, then look at the spark plugs, and run a compression test, it may just be time to change the plugs or a valve has stuck open, then ignition coil output, a weak spark can also give a misfire code, then the injectors themselves, dirty injectors can cause a misfire also. HTH
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