So my car has 900 miles on and twice now it has had the temp gauge jump to the 3/4 mark. When turning the car off it only resets to the 1/4 mark but some time during being off it goes down to zero as it should. I took it to the shop yesterday and of course it didn't happen, nor did it throw a code at all so that was a waste of time. My MPG or drivability have not been affected by this just can't figure out what is making this happen. Has anyone else experienced this?