Tachometer Problem - Most Likely?

[SkyKing]

Chances are you've got a connection with an improper crimp in it. Re-crimp the connections where the short wire leads connect to the aircraft wiring for the longer journey to the tachometer near the mag and you should solve the problem. On the rear of course, you'll have to open up the rear hatch. No big deal, but while you're in there check to make sure your shop put all the screws back where they belong. They are forever famous for leaving things half-assed.

SkyKing