2005 Volvo Cummins15 CM870 TURBO SURGING UP AND DOWN

[Going crazy]

Hello everyone , I wish you all a happy new year !!I recently did an overhaul on my 2005 Volvo Cummins Isx 15. Injectors, pistons, new head, and new turbo (turbo shut closed broken). l replaced also the turbo along with exhaust sensor/turbo pressure sensor/ turbo air control valve and actuator. FYI I’ve swapped 3 different turbos.

TURBO KEEPS SURGING UP AND DOWN WHEN ACCELERATING AND JUST IN IDLE THERE IS SOOO MUCH BOOST IT SOUNDS LIKE YOU ARE NEXT TO BOEING AIRPLANE .

SYMPTOMS: In neutral when pushing accelerator pedal RPM wont rise above 1400 and turbo actuator surges up and down .
When driving there aren’t rpm limitations but actuator behaves in a similar fashion surging up and down with soo much over boost. Truck is automatic and it has soo much boost that truck won’t even shift properly at times . I am not running the truck FYI just test runs .

HAS ANYONE RAN INTO A SIMILAR ISSUE. I NEED GUIDANCE PLEASE!! IS IT AN ECM ISSUE ? IS IT A HARNESS ISSUE ?