The scenario....

Whilst out mapping my car with karl we noticed the peak boost and boost held was getting gradualy lower and lower (starting @ 22psi peak / 21 ish held down to 20 peak / 17ish held). I sent my exhaust housing away to be checked on the basis that the wastegate arm was twisting under load/heat but it seems this is not the case.

The problem may be resolved by fitted a new -31 Actuator, but this has not been tested yet. I guess my reason for posting was to see if anyone else has had this problem, and if so, how did you resolve it. Hopefully the new -31 will sort it but if not, any ideas as to what else could cause this to happen?

T34 / EFi L6 Webber / 1.9cvh btw