I have a problem with my speedo. This started a couple months ago, but haven't had time to get around to fixing it. It always reads higher than the actual speed, but not consistant. It can be anywhere from 3 to 15 mph off, which is causing shifting issues. I replaced the vss in the differential being it was cheap and the most obvious place to start. Still not right. When I get on the throttle, it will run up to 35-40 quick while I'm still around 25 or so. Then my speed will catch up to speedo- but never right on. I took it out on the parkway and I immediately buried the needle in the odo, even though I was at 65. I verified my speed with GPS. Searched around and can't seem to find any threads with similar issues. Anything else electronic that I should check, or the speedo drive? I don't get any abs lights or flashing od light.The needle doesn't jump around or do anything out of the ordinary. Any help would be appreciated.