There has been some mention of using GPS and Radar for calibrating speed. How is this done? Who do you talk to? My speedos and Perfect Pass are off a couple MPH's and even the temperature readings on both are too. Anybody figure this out? Thanks.
Chris, how do I know which one is accurate? The manual tells you what to do after determining what the correct speed is. There is no mention on how to actually go about getting a GPS or radar check done. What if they are both off?