I've owned this 1988 Sammy since 1990. I don't remember it getting good gas mileage at all( aronud 15 mpg right now). i have done the basic spark plugs, wires, rotor, and oil change. Is there something esle that i am missing? I read on here about pulling CEL codes. Also it just started overheating on me. I changed the thermostat today. still overheats. Is it the radiator? water pump? Sammy has 97000 miles one it.