2006 GTO, cam, cold air, headers, etc. tuned by "MASTER!" tuner. We turned speed limiter off and car will run up there fine. Trouble is the Speedometer (both the number and the dial) go to a certain point (ie 155) and don't go further even though the GPS (and definitely we know)is showing faster. Any ideas?
Did search the forum. Couldn't find anything. If someone has already addressed this issue, thanks in advance if you'll let me know.