I've got a problem with a judder when normal driving (almost like a misfire) also when stationary and the car is ticking over if i accelerate sharply the engine dies for a second then picks back up. I've changed the plugs, dizzy cap, rotor arm and the coil looks brand new (haven't had the car long and it looks as thought the previous owner has tried to rectify this problem). Its been in the garage today for a fault diagnostics. The mechanic said it was showing a fault on the hall sender unit in the distributor but said he looked at it and that too looked brand new, he's checked all the wiring and checked for air leaks, this problem is getting really annoying now

Can anyone help me please?