Over the last week, my engine coolant gauge has gone to the dark side. At any given time after start up (the car can be dead cold or very warmed up, doesnt matter) the coolant needle shoots up to high, pauses, then shoots back all the way to low, back up to high and on and on. Other times, the needle behaves itself. When the needle does hit high, a fan comes on under the hood and clicks off once the needle is off of high. Now the check engine light is on. it was 28 degrees where I live last night and I just went out and started it and it went straight to high. Impossible. I have an appt. to bring it in Wed., but in the mean time, any ideas??
Thanks guys