As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER MANY HOURS OF AEROBATIC FLIGHT, SMALL TRACES OF OIL MIGRATED INTO THE MAP LINE BEHIND THE CYLINDER. EVENTUALLY THIS CAUSES ERRATIC OR COMPLETE LOSS OF THE MAP INDICATION. THERE IS NO SOLUTION FOR THIS OTHER THAN HAVING THE GAUGE REPAIRED AND BLOWING OUT THE LINE.