That damn code is a PITA. It's just a catch-all
Suggestions include clean MAFs/TBs, check for vacuum leaks, O2 sensors, spark plugs/injectors, fuel pump, oil pressure (gallery gaskets).
However, I notice you said p2631 is a sun sensor code? I'm seeing that as an O2 sensor code. So I would start there
Ooops... I read that wrong. Did you mean
P2631 or
B2631? The P code is O2 related. I know your car is aging (mine is a month away from 10 years old) so there's quite a few random things that could have failed or be failing.