My tachometer started acting up.
At engine idle it would read zero revs and as you slowly open the throtlle the revs jump up to 3500 and then settles around 4000 with the engine probably at 2800 or so which is where we usually cruise.
I looked at the sender unit, pulled the wires off and noted significant corrosion. Cleaned terminal with fine emery paper and sprayed liberally with Corrosion Block. Restarted engine and to my relief the problem was fixed with tach behaving normally.
I am thinking of spending some time with the engine and doing that with all the electrical connections. Sooner or later they will all corrode.
BTW I replaced the oil pressure sensor (very surpising but it was only about $9.50) and the engine oil warning light and buzzer are working normally again.
Dionysus C387 #8
I had the same experience and