Irregular performance

Hi,

At time when driving my Octy RS Ive noticed that the power can go flat, like all revs and no boost - this normally happens randomly, whether hot or cold. :(

At times I can be driving along fine, I can hear the turbo pick up when ferrying around quickly, and the car is quite responsive (you can feel the torque). Then the following day it can be quite the opposite, like there is no turbo, you can here the turbo spooling but there's no 'get up and go' it feels flat like driving a NASP.

This seems to happen in nearly all gears, and like I said can occur when the car is hot or cold.

It does seem to be worse when it is cold, but as its very stuttery/jerky for the first 5/10 mins when starting from cold I'm not sure if it's related or not.

Has anyone else experienced this? I'm not sure what to check, I've seen mention of cleaning the throttle body etc. but I would have thought this would degrade the cars performance all the time?

I suppose a VAGCOM check would be advisable too - just wondered if there is something obvious for me to take a butchers at.

Thanks in advance