HDG TRACK ALTDEV.

Narrative

I WAS FLYING THE VICTOR AIRWAY FROM BUFFALO TOWARDS XYU. I WAS COUPLED WITH THE BUFFALO VOR ON MY AUTOPLT. I WAS IN IMC CONDITIONS AND I WAS DISTRACTED BY PAX. MY AUTOPLT AND DIRECTIONAL GYROSCOPE UNCOUPLED. I WAS CALLED BY TORONTO CTR TO BE INFORMED I HAD TURNED 130 DEGS. I WAS STARTLED TO SEE MY GYROSCOPE WAS BOUNCING BACK AND FORTH AND ADVISED TORONTO CTR THAT MY AUTOPLT OR GYROSCOPE HAD MALFUNCTIONED AT WHICH TIME I TURNED BACK ON COURSE WITH THE USE OF THE VOR ALONE. DURING THIS TIME MY ALT ALSO APCHED 6400 FT; OF WHICH WAS ALSO CORRECTED. I ASKED CTR TO KEEP ME ADVISED OF MY HDG UNTIL I COULD VERIFY WHICH INSTS WERE WORKING. THE GYROSCOPE EVENTUALLY SETTLED DOWN. I SWITCHED THE AUTOPLT OFF AND FLEW NORMAL. LATER I TURNED AUTOPLT ON AND IT WORKED. HOWEVER I KEPT A CLOSE WATCH THE REST OF MY TRIP. SINCE THIS TRIP; I AM HAVING THE AUTOPLT AND GYROSCOPE LOOKED AT. I BELIEVE THE INITIAL CAUSE OF THE PROB WAS AN AUTOPLT MALFUNCTION. THE FACT THAT I WAS DISTRACTED AND NOT PAYING AS CLOSE OF ATTN AS I SHOULD HAVE ALLOWED THE ACFT TO MAKE THE SLOW TURN UNNOTICED. LESSON LEARNED IS: NOT TO OVER RELY ON THE AUTOPLT; AND WITH OR WITHOUT DISTRS THE PIC MUST ALWAYS AVIATE AND NAV.