The fuel filter is located on the underside of your Rainer near the fuel tank. On your engine there are 4 spark plugs on each side. You will need to remove whatever you think is necessary to access the spark plugs. When changing plugs on your engine it would be a good idea to replace the spark plug wires also. With the 90k spark plugs it makes it very hard to get the old wires off the spark plugs without damaging them.