Ive got a 94 IDI 7.3 Turbo. Just got a brandnew rebuilt injector pump because the old ended up getting clogged. Ive drove it about 150 miles and about 50 ago you could start to see the oil pressure was goin down. If it would idle it would hol pressure but if you got on it more it would start to loose it.The truck burns or uses a little oil but the last time i checked it it was a bit higher. What could it be? How would diesel fuel be getting in there?