Well here goes while driving down the highway Sunday my truck started to run very rough and I noticed white smoke comming out of the tail pipe. After returning home and parking I noticed small drops of oil dripping off the back side of the motor a spot of 3-4 inches and drops were pea sized. The truck starts right up and gets to hwy speeds pretty easily does anybody have any suggestions. Injectors,EGR cooler I'm not sure where to begin. The truck has 255k on it and the only thing ever done to it was a waterpump.