I think its normal, i wish i could tell you why. But my truck used to blow out smoke like that every once in awhile before my deletes, i recommend just following through with all the deletes and youll be set.
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2007 6.7, Cab and Chassis Reg. cab, 4x4, G56, CM 11ft bed, Valair, baffle gone, Power Pup, Mp8, Quadzilla Boost Fooler, EGR Delete, DPF???