Toyota Repair: 1996 GEO PRISM, radiator hose, gas mileage

Question
MY CAR HAS AN AMAZING 240,000 MILES ON IT AND RUNS GREAT. ONLY
PROBLEM IS CAR IDLES FAST.I NOTICE THAT TEMP GUAGE DOES NOT REACH MIDDLE OF REGISTER ANYMORE. CAR HEATS UP INSIDE,BUT IT TAKES ITS TIME DOING SO

I WANT TO LOWER THE IDLE TO SAVE GAS AND ENGINE WEAR

ANY IDEAS?

Answer
The engine needs to get to operating temperature for the idle to come down and to get better gas mileage, the idle is adjusted by the computer, if it doesn't get to the right temperature it will increase the idle speed, the first thing you should do is to replace the thermostat, it's located in the housing where the lower radiator hose goes to the engine.