It was probably malfuntioning at first. Mine went the other way when it malfunctioned, on the highway, doing 80.....freaked me the hell out !! Pulled over to the side, switched of the engine. It stayed at 3 when I restarted till I got home. After I parked it for awhile it came back to normal operation as you have described. If it acts up again the sending unit will be replaced my heart can't take to much of that kind of shock