Very true one of the reasons I went with a 12 valve over a newer diesel haha May just end up pulling the injectors and inspecting them at least till I can buy new ones. I did notice what looked like oil seeping out of one of the line fittings on top of the #5 injector but I agree with you that if there was oil and fuel mixing then there should be fuel in the oil which it doesn't really seem like there is. I did add some power service diesel kleen to the tank before I did checked the timing and the problem got worse so that might have something to do with it. I also noticed when I did the lift pump that it had red diesel the fuel bowl for the pre filter which from what I understand is off road diesel. I have filled up the truck twice since Ive owned it both at big chain gas stations so I thought that was kind of weird.