So I've been getting really poor gas mileage, my gauge is busted and whenever fuel gets low, the truck starts to shake violently. It used to be when there was about 10 gallons left, now it's acting up after only using 16, which is not quite half a tank. I think the fuel pump is going out, I've never replaced one so does anyone have any ideas or advice for an aftermarket model, replacement advice and the general procedure I need to follow? Or maybe any ideas if it's not a fuel pump? It's a 1993 Ramcharger 5.9 Magnum with a 34 gallon tank.