So I was driving my e38 and all of sudden the car stops on the side of th road. Waited a few minutes and the car started again to bring me home, thank GOD! I realized the fuel pump was sending weak pressure. Finally I decided to put in a new pump. When I took out the old pump, to my surprise, there was this brown gunk in the tank. It seemed like a mixture of rust dust and just build up of a dirt like substance. In any case it was clogging up my pump, filters, and of course injectors. Does anyone know a way of flushing the fuel tank without removing it from the car?