Hello, I have a 1983 240D, manual transmission. The Speedometer seems to read about 8 - 12 miles slower than the real Speed. The wheels on the car are OE. I have had the car since about 130,000 miles. It now has 150,000. The previous owner said this has been a long running issue that they never bothered to look into. I get confused sometimes at my real speed (especially if the police are behind me!). Any tips on what I should do? Replace cable? Or replace Speedometer? Thanks!