Piper Autocontrol IIIB

Flew to dinner today with an outside temp of 10F. Auto pilot worked OK on the
trip out (plane came out of a 45F hanger). Parked for dinner for about 2
hours. The autopilot didn't work on the way back. You could feel the clutch
take hold but no corrective action to follow the bug. Simple roll control
didn't respond either. Well, about 20 minutes into the flight home, it started
to work. OK all the way home.

So, is it on its last leg and I should pull it and see if I can get it fixed?
Fixed where? Or is the low temperture (it was outside for 2 hours in 10F) the
problem? If it's low temp, I'm tempted to let it go since I don't often fly
there.

Chuck