I have a TP20 Simrad tiller autopilot for my Catalina 27 which is one size larger than normal. On our way back from Catalina Island we were motor sailing in calm seas at about 51/2 knots into the wind when the autopilot started adjusting 5 to 10 degree port and starboard (sometime more) every few second all by itself. I shut down the pilot for about an hour and when I started it back up again it was doing the same thing. Anyone have any ideas on what to do. Except send it back. Thank you, JOHN