CM871 surging/shaking at idle

[Mk5Spnd10]

Hello.

I’ve got an ‘07 W900 that I installed a CM871 in. I didn’t know much about Cummins engines when I bought the donor motor and thought an ISX was an ISX… Anyhow after making the wiring, hardware and ECM reprogramming I’ve got it running. It’s got an overlay that claims to be the mm ECM deregulation. The problem I have is this thing sounds horrible and shakes the whole truck at times when unloaded or parked throughout the entire RPM band. I did have some errors with the data being copied into the turbo maps they didn't go thru, so I presume my problem is low end boost related as I can’t hear the turbo spool at all until under load. Fuel system tests indicate everything is good, valves adjusted, and it pulls 100,000# without any problems. Boost pressure is around 38 when pulling. Any suggestions on where to start looking for the rhythmic shaking? The errors in Calterm came when copying maps from CBR_SOI_ALPHA1_TABLE to CBR_SOI_Chi4_TABLE. It said the parameters were exceed or something along those lines. Thanks in advance!