I was flying smoothly out of Tokyo and at 32300 feet my autothrottle went off and I started to descend...I have Lnav and Vnav on and ap on..I was on course and the plane didnt want to climb back to 32300 it was the 747-400 by PMDGAnyone else have Autopilot errors?

Yes today!I was out of KSFO on the SHORE1.SAC SID for FL330. OPT CRZ LVL was fl327.THR REF and VNAV SPD were green. When reaching FL330 SPD & VNAV PTH became green, but the aircraft didn't stop climbing! I manually switched to V/S and brought it back to fl330 where I enganged VNAV again. From then the aircraft held the FL.Strange. Never encountered such problems before.@lex

Yeah, I've had the rare glitch like that. They will likely never get fixed, since there is no known repro case... :(However, in your case, the correct thing to do would be to press VNAV again - an A/T mode will be auto-selected.- Bill

yeah yeah, thats the curse of complex systems/programms, the more complex they get, the harder it becomes to explain and find problems