black smoke and a cough

[slowpoke]

isx cm871 emmisions all reconnected did one run Toronto to jersy truck ran good empty down but noticed stacks were black way more than when i was del*ted. loaded getting on intersate truck coughed 4 times fraction of a second lose of power. had warmed engine to 180 before i left. i could see black smoke about 2 seconds after full throttle trail to back of trailer then stop. i did install used doc and dpf wanted to make sure egr wasn't going to leak and destroy brand new ones. can an isx still produce black smoke through a dpf filter if something else is bad. going to pull egr valve. i hadn't changed delta p . or exhaust back pressure sensor yet. will replace dpf with road warrior just want to make sure everything else is fine first. so can an isx 871 roll black smoke with an intact dpf is main question.