ISX15-CM2250 running rough cold help?

[68shifter]

Hello.

Scratching my head on a 2012 T800 with an ISX15@450hp-CM2250 with 500k.
Customer bought it at an auction and appears to be really well taken care of. It is de-mandated and tuned to 550hp, but I have really no other history on the truck. It has block off plates and a gutted filter.

It runs like crap cold though. Lopes and Surges coughing black smoke, once it is warm though it runs great and no smoke. No engine codes through insite.

I have leaked down injectors, cut-out test, new fuel and filters. Someone already replaced the fuel pump actuator, pressure sensor as they all look almost brand new. I even sent the injectors in to be tested and clean bill of health. I also can't find anything in the harness, overhead was rigth on and cam looks great.

I'm at my wits end, I suspect it is the tune but have never run into this before. I really cant see it being something deeper but any help would be appreciated.
Thank you