I am sure many of us have gone through this experience where the gas lid appears to be stuck. Many G35 owners have made this a huge issue and have been calling Infiniti for instructions. Solution is very simple….
According to the owner's manual, put the key in the driver's side door and turn it towards the rear. Unlock the doors using the door master unlock switch. Use the keyfob atleast twice after this step. This will override the factory settings or in simple words reset the module.
In case this override doesn't do any good, this means the gas door actuator is bad. You can order that from the dealer (actuator part # 78850-AM800). In the mean time you can reach from inside the trunk and pop open the door.
