As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN VNAV, B A/P ENGAGED CLEARED TO LEVEL OFF AT FL 260. AIRCRAFT LEVELED OFF 90 FEET LOW, SHOWN ON BOTH PRIMARY FLIGHT DISPLAYS. THE A/P MADE NO EFFORT TO CORRECT AND REMAINED 90 FEET LOW. CHANGING TO THE "A" AUTOPILOT MADE NO DIFFERENCE. GROUNDED - YES. PERFORMED B737-900 FIM 34-61 TASK 801. L FMC FLAGGED R FMC FOR A RATE FAULT ON FLIGHT 2, NO OTHER FAULTS. FAULT IS AN INTERMITTENT FAULT, REF FIM 34-61 TASK 837. ETOPS GRD VERIFICATION NML PER SAME.