)) I have a 1985 53i and the tach has been giving incorrect readings. Sometimes it reads the correct rpm and sometimes it doesn't. For example, idle rpm is around 700. When it malfunctions, it reads about 200. At faster speeds when the rpm should read around 2000, it reads around 1000. It doesn't affect the driving, it must just be a bad gauge or linkage, or something else. Any suggestions? Cost of repairing? Thanks,Jim