My gas mileage has dropped drastically. My temp gauge reads lower than it has before. When fully warmed up, upper and lower radiator hoses are about 20 degrees different in temp. I going to assume my thermostat is wonky. Does that make sense? If I replace it, should I go with Motorcraft from the Ford dealer, or is there a better thermostat? A $10 price difference isn't the issue. I am often VERY far from towns and don't relish a stuck thermostat. My present thermostat is a two year old Motorcraft.