A fuel consumption analysis was a type of diagnostic that measured the fuel usage of a starship.
In 2372, Lon Suder ran a fuel consumption analysis in USS Voyager's main engineering section per B'Elanna Torres's orders. He used it as his alibi for the murder of Crewman Frank Darwin, saying he worked on it all night, including at the time of the man's death. (VOY: "Meld")