hesitation and excesive engine rock golf gti T

[Parker]

I bought a Golf Gti T (99) a few months ago and have had heaps of trouble with an intermittant fualt. When problematic there is heavy hesitation. The car judders, does not accelerate and i think the fuel consumption drops although this is a little hard be definate on. If it's playing up there is also exceesive engine rock at idle, enough to make the front seats shake. There are days when the car runs perfect and others when its a nightmare. I,ve changeg the plugs (genuine VW), timing belts, oil/filter, run fuel system cleaner through it. There are no fault codes on the computer. I,ve cheked this twice! I've also replaced the MAF sensor as I had read that sometimes this can malfunction within the operating specifications and thus not log a code. One garage suggested it could be a coil pack, but wouldn't this also log a code? Has anyone got any ideas!!!!! I've spoken to the local VW dealer and all they can tell me is that they can take it apart and have a look but that its gonna take a lot of time, cost a fair bit and can't guarentee a result cos it's an intermittant fault. (They won;t give me a quote). I'm struggling with this one at the mo. Please help!!

[Col]

Engine rock = lower 'dogbone' engine mount.

As for the bad running, coil pack intermittant failure ?