Please help. I have a car/scanner light on my dash showing. She still runs fine with no limp home mode or any loss of performance. The only thing I have noticed is that my temp gauge rises higher when doing motorway speeds then lowers in town traffic. Whereas before the gauge remained constantly fixed at the first red line on the gauge. Now settles at about the 80degree mark. Is there a sensor I should be looking to check or replace. Or is it more sinister. Thank you in advance.