Engine Hasitates and bucks

Hi, my cars keeps "jolting" as I accelerate to aprox 30mph then yesterday it lost complete acceleration, however the rev counter was still working and it drove again after restarting the engine, though the jolting continued and it cut out twice more, a light has appeared on my dash but I havent yet looked in the manual as it is elsewhere, does anyone have any suggestions as to the fault? Any advice would be appreciated. Thanks, charlie.