High exhaust pressure

[lwilder27]

I have a ISX12 CM2350 that is failing the regeneration analyzer due to high exhaust back pressure. In the report its showing 165-175 Inhg.

Heres a list of what I have done so far.

The exhaust pressure sensing tube was plugged, so it was replaced at the same time I did exhaust manifold gaskets. It has a new EGR valve, IMAP sensor, EGR diff pressure sensor, EGR pressure sensor, and exhaust gas pressure sensor. The turbo was just rebuilt and I had the DOC/DPF cooked and flow tested. I checked my decomp tube, all is clear, used a mirror and checked the SCR and looks good.

Ran the analyzer again and monitored exhaust pressure at 160 inmg and took the exhaust pipe off at the inlet of the DOC and saw no pressure drop.

In the analyzer report, the EGR valve remained at zero percent for the duration, which tells me it would not be a resitriction in the EGR system. Is this good logic or am I miss understanding?
The only culprits I can think of are a bad turbo rebuild and or actuator install and EGR restrictions.