The gas door locks and unlocks with the rest of the car (similar to the hatch). If you can unlock the car then the gas lid should be unlocked unless the pin is stuck. I'd try JC's suggestion above, but if you can't unlock the passenger door and hatch because the battery is dead then you'll need to replace the battery to get in the gas lid.
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2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed | |