The tach has always worked perfectly on this car. My dad bought the car with 90,000. It now runs/looks better than ever with 256,000. Today the tach just quit. I did replace the inline fuel filter today. Is it possible I knocked off a wire or is it possibly a sending unit problem.It looks Ok as far as wires and hoses. From what I have read in past threads the 85 has a different type of sending unit(not with the multi-pin plug). Is this correct or where is a good place to start looking or tests ? Thanks for any ideas.