A system for monitoring performance of a fuel system in a vehicle includes a plurality of sensing modules that periodically sense data from a plurality of control systems in the vehicle during a predetermined evaluation period. The system includes a control module that analyzes the data after the evaluation period, generates performance ratings for the control systems based on the data, generates a set of values for the performance of the fuel system based on the performance ratings and a plurality of predetermined fuzzy logic rules, and generates a control signal based on a numerical analysis of the set of values. The system includes an indicator module that indicates in real time whether the performance of the fuel system conforms to a designed performance of the vehicle based on the control signal.