As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT CABIN ALTITUDE BEGAN TO CLIMB. BEGAN DESCENT AND REGAINED CONTROL OF CABIN PRESSURE. RETURNED TO DFW AND LANDED WITHOUT INCIDENT. FOUND INTERMITTENT N3 INDICATION FROM RIGHT ENGINE. REPLACED NUMBER TWO ENGINE N3 TACH GENERATOR PLUG.