Engine hesitates at high revs

[GTBTTDavie]

Hi I have just bought a 1996 GT-B TT and have notice when it gets into the higher revs, round the 4500 i think when the second turbo is kicking in the cars sort of hesitates for a second then goes, then does it again......help needed please

[quicklook]

fouled plugs, bad ign. wires, clogged exhaust, bad cat or cats, clogged air cleaner could be a lot of things.

[GTBTTDavie]

cheers thanks for info