1. A method comprising: determining, using a portable octane analyzer, a first octane measurement at a first nozzle, wherein the octane analyzer is removeably attachable to the first nozzle; and wherein the first octane measurement measures a fuel sample that is being dispensed from a fuel pump; determining, using the portable octane analyzer, a second octane measurement at a second nozzle, wherein the second octane measurement measures a fuel sample that is being dispensed from a different fuel pump; comparing, using the portable octane analyzer, the first octane measurement and the second octane measurement with at least one standard octane rating; determining, using the portable octane analyzer, that the first octane measurement fails to match the at least one standard octane rating; transmitting, via the portable octane analyzer to a user, an indication of an error in the first octane measurement; and displaying, on a display, the indication of the error.