As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE FL380, NUMEROUS PRESSURIZATION BUMPS EXPERIENCED OVER 1-2 HOUR PERIOD. CABIN CLIMB INDICATOR WOULD FLUCTUATE BETWEEN 500-700 FPM CLIMB AND 500-1000 FPM DESCENT. CABIN DIFFERENTIAL AT APPROXIMATELY 8.3-8.4 (BOTTOM/BELOW ORANGE ARC), CABIN ALTITUDE APPROXIMATELY 7000 FEET. GROUNDED - YES. REPLACED L/H PACK TEMP CONTROL VALVE PER B737-900 AMM 21-51-10.