Ok guys, I have been reading every post possible trying to determine what I need to do before I replace my injectors. For the record, I just purchased a 2002 Chevy Silverado 3500 with the LB7 Duramax. It has 153,00 miles on it and the first set of injectors were replaced, by Chevy, at 84,000. I paid $9500 for the truck as it is a dually with a 11 foot service bed. I followed the advice of many of you and started from the beginning. I filled the truck with Chevron diesel and poured two bottles of Sea a Foam in each tank. I changed the fuel filter. I checked all the vacuum lines and all the electrical connections. I performed the oil on white paper towel test to determine if there is fuel in my crankcase. There is. I have no loss of power while towing a load with the service engine light on but have noticed a considerable drop in oil pressure. The truck starts up right away, cold or hot. It does not smoke, white or black. So...what do you guys suggest I do next? I'm prepared to absorb the cost of injector replacement but need to be sure I am spending my money on the right problem. Please advise.