i have a 6.2 diesel in my rig. i was wondering what the redline is. also on a 40 degree day if my rig has been sitting for an hour or so, it will start with ease but seem to idle low and miss on one cylinder. smoke comes from one tail pipe. (ive got true dual exhaust). it never smokes excessively under a load, but my mileage has fallen from a consistant 17.5 to 18 city to 15 to 16 mpg. maybe its time for another injector rebuild, or age is taking its toll. what is the life expentacy of a 6.2 diesel?