I have an 02 with 136000 miles. only mods are superchips programer. Three weeks ago came back from Atl my mileaged drop by 2 mpg and oil pressure dropped to 20-25 psi. Had to use it at work the next week, it filled the case with diesel and poured out on customers new driveway. Truck ran rough that day but since idles and runs fine but still leaking diesel in to case. Not sure if its an injector of pump. Any help to figure it out would be greatly appreicated.