Boost fluttering at part throttle accelleration?

[2QUIK6]

My boost has started to flutter up and down at part throttle accelleration blasts of say about 10 lbs...it will flutter up and down say to 12# then back to 9# then back to 12# back and forth. It takes it about 1 second to drop down to 9 and then pop back up to 12 so its not like boost spike.
I have a BstC controller with 1 stock solenoid, with a THDP and the hole has been opened up to 15/16" with stock turbo.

Any idea what the cause may be? I just recently put on an LS1 MAF and Trans+ also and this started about the same time.
At WOT its fine, only part throttle problem.

 

[tminer]

I get the same thing when my wastegate rod is too tight. I loosened it up and added external spring(s).

Tom

 

[2QUIK6]

Thx, I'll try loosening it up a bit as the BstC controller is barely turned to the 2nd mark for max boost on pump gas.

 

[2QUIK6]

That seemed to fix it. Thanks Tom