Jerking at high boost

[Zsolt]

My car is an 88 5ktq with an SJM chip and 1.8 bar WG spring. Recently the 
car started acting up at high boost. It usually happens at full throttle 
and as soon as there is enough boost just below 3000 RPM, and all the way 
to redline. The weird thing is that it only seem to do it when the engine 
is hot. (I don't mean that I rev it like that as soon as I start the car up)

Any BTDT? Please respond to me directly, because I have my quattro mail on 
hold at the moment.

Thanks in advance,
Zsolt