High idle, high fuel consumption, could be a sensor?

The rear makes a thumping sound when applying breaks only. Normal idle is close to 0. Now start up idle is over 1 and bogs itself down when temperature reaches third line. Will use almost two lines on gas gauge going 18-20 miles with highway speed of 55 MPH and in town at 30 mph for 5 of the 18-20. Some sensor has popped check engine light on with code saying a temperature sensor is too hot. The front driver tire had steel belts showing on the inside of tire. Oil is leaking out down front of engine from the oil filter housing gasket. Is there a better one I can replace faulty one with? All these things have me only car making me worry it will leave me stranded somewhere far from the little country town I live in with not one accommodation so traveling next town is only way to get parts before car stops working and food and gas and work. Please help me out with these problems. Thank you for your time and knowledge.