Vehicle in question is my uncles truck bought new, a 2005 Dodge 2500 with the 5.9 Cummins common rail, as of yesterday it had 415,815 miles, mostly highway miles and a good bit of heavy towing over the last 13 years. It has been very reliable, still on the original 48RE transmission, never been rebuilt. Its bone stock except for a 4 inch exhaust installed at around 250k miles. My question is regarding the injectors, it has the original injectors and CP3 injection pump. for the past year or so, we've noticed a puff of black smoke at startup and moderate smoke on acceleration. We did take the cat off when we did the exhaust, but these common rails burn pretty clean compared to previous engines, so Im suspecting injectors. Ive heard that if an injector on these engines goes out, itll fry a piston in no time. So what do you guys think, should he have a good diagnostic scan done to see if its the injectors?