|
I have a 86' 911 Cab that had the same bouncing tach needle. It was initially diagnosed as a short in my battery. When the battery was removed to put in a new battery, the ground wire to the battery was found to have been rusted and not grounding the car properly. New $ 18.00 strap installed, no more bouncing tach! Good Luck.
Huey58
86' 911 Cab
|