Golf MK4 1.4S 2000 W

I have a 2000 (W reg) mk4 1.4s 16v with 50k on it, my problem is that the engine 'judders' when standing still & it feels as though it might cut-out but never does. It started doing this intermittently about 2000 miles ago but does it nearly all the time now! Does anybody know what may cause this?

Thanks :confused:

I have a similar problem with my mk4 Golf. I haven't confirmed it yet but I think it may be caused by a fault in the AC, as when I turn it off the judder stops (although not immediately so this may be a coincidence).