1.8t golf 2003 surging problems

[madgolf]

hi guys could anyone shine some light on my 1.8t golf 2003, we seem to have a problem when i'm driving along and then put my foot down hard the boost comes in but if i take my foot off slightly and hold it there it drops in revs and then seems to pick up on it's own just like you've put your foot back down on pedal (it hard to explain) it's had a new maf and i've cleaned the a.i.t sensor, i took the car to my local vw dealer but no joy they did not know what it was but mentioned something about a sensor in the manifold, by the way the car does this at any revs or speed, 43.000 miles           please help....thanks

[Don®]

If you have access to a vag-com try logging block 002, 003 and 115

Your e-gas pedal may be on the fritz.

[madgolf]

just had vag-com done and guess what no faults found,told vw they think it could be a map sensor problem,also its has just developed a high pitch noise coming from the thottle body when the ignition is on but as soon as it starts the noise dissapears what do you think? thanks