Methods and systems are provided for conducting a fuel tank diagnostic. In one example, a method comprises sealing a fuel tank of a vehicle, retrieving data related to fuel tank pressure from a crowd of vehicles, and indicating the fuel tank of the vehicle being diagnosed is degraded responsive to data related to fuel tank pressure from the crowd insufficiently correlating with a set of data related to fuel tank pressure from the vehicle. In this way, fuel tank degradation may be indicated without coupling the fuel tank of the vehicle to atmosphere, which may reduce a release of undesired evaporative emissions to atmosphere.