A couple weeks ago my 200 4.3L s-10 started running colder than usual. It was running around 200, but it sits at 175 all of the time now. I've also noticed my gas mileage has dropped about 5mpg too.
What could be causing this the Truck as 58K on it and has been well maintained since I bought it 43K ago. Is it something as simple as the thermostat? The heater still pumps out plenty of heat too.
Thanks