Hi,

I seem to be unable to unlock my doors with the mechanical key on a 08 G35X sedan. However, if I hold the key to the right the windows do open. Anybody have the same problem and any solutions?

 

I believe there is still meant to be a physical linkage from the key cylinder straight down to the lock itself. (That would come in handy in case of a dead battery.) My '05/'06 manual shows a "key lock rod" on the driver's side but gives no further description. Perhaps one end of your linkage has become disconnected?
Good luck.