ISM 320V 2010 No Boost

[Lakepremix]

Good morning. In desperate need of help. Have a 2010 Kenworth ISM 320V Mixer truck. Had a bunch of dpf issues. Had the filter cleaned. Worked great for 2 months. Then started needing a regen daily. Found the dpf pressure differential switch was bad (thus thinking it always needed a regen). Changed out switch, all codes/faults are cleared with no new but now have no boost whatsoever. Bought insite to try to figure it out better. When accelerating, we get a air fuel control derate. Mechanic got a max of about 4 psi of boost. There wasn't any loud noises etc, just pulled out of yard and half way down the road lost all power (no power now, revs slowly in idle etc).

Am completely lost as to what to do. Can't hear any turbo spooling but turbo was inspected with no noticeable problems. VGT was removed and calibrated with no faults. Just absolutely lost and was looking for any suggestions on data to look for in insite that could direct us towards a potential fix without tearing into engine.

Please help so my sleepless nights improve!