That will depend how hard you are running and what gear? If your in D and just cruising at 75 mph, it should be very conservative. Your seeing my at WOT during a drag race. This shouldn't be on the highway unless your in Mexico. You should be in the 11's or 12's unless your running leaner. Remember at idle the car is factory set at automatically at 14.7 so that shouldn't freak you out. It's under load that you want to see where your readings are at.