Car Stutter, Please help

[Chrisuk]

Hi there, thankyou for taking the time to redmy quetion, my mate has a 1994 Beemer 520 Manua and it has an annoying problem, When accelerating even moderatly it will stutter. it is like someone pullingthe spark plug leads out and immediatly putting them back in again just before the engine totally stops, he is nearly in tears, he has been to BMW and they run a full electrics check and all appeared to be fine so they charged him for the priviledge of using their space however it still has a problem, Can anybody help please, thanks Chris