Mine read 250* on a scanner but looked fine from the dashboard gauge.

 

fixed, had a leak at the gasket on the intake, also had a fuel injector that wasnt seating properly, due to the bracket for the fuel rail. i hadnt noticed it was being pulled up as i tightened the bracket. all prior tests for leaks didnt show anything, so i didnt check into it anymore, glad i did it once more. no more knock sensor codes, no misfires. all is well.