As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CRUISE DESCENT OUT OF 12,000 FEET A NOTICEABLE LOSS OF MANIFOLD PRESSURE (33 INCHES DOWN TO 17 INCHES) WAS EXPERIENCED ON NR 2 ENGINE. THE APPROPRIATE DRILL WAS CARRIED OUT AND THE ENGINE WAS KEPT RUNNING AS IT WAS PRODUCING POWER. AN UNSCHEDULED LANDING WAS MADE AND THE FAULT FOUND AND RECTIFIED.