hi mate i have just had the same problem and after bying all sorts of things from coils to maf sensors it turned out to be the lamba sensor this is located at the back of the top of the engine it looks like a upside down spark plug with 4 wires coming out i bought one for £42 and my car is fine did u have problems with power too mine would stick at 2000 rpm then shoot like a turbo and the engine would judder like it was going to stall then rev itself

hope this helps

Sin