Rev iPhone app
This app is probably the best iPhone tool for car diagnostics. It features a great visual design that enhances the user experience. Also the list of features and monitoring options is huge. You can watch in graph your accelerating, braking and cornering forces and, combined with the GPS tracking, you can view a visual map that displays your acceleration data in relation to your location on the road.
With this app you can monitor RPM, Vehicle Speed, Fuel Consumption, Engine Temperature, Fuel Pressure, Engine Load, Throttle Position, Intake Manifold Pressure, Air Intake Temp, Timing Advance, Fuel Level, Mass Air Flow, Barometric Pressure, EVAP System Vapor Pressure, Fuel Trim and Boost. Depending on your vehicle, some of these parameters can’t be shown.
You can even record your performance and compare it later with the data gathered after a tune up or after adding a new part or different set of tires. You can also check your engine codes and even perform a one-button reset of your codes and Check Engine light. You can find out more about this app from its developer by following this link here.