You are are correct - the ECM/PCM uses fuel injector pulse width to measure fuel usage...not sure how that other guy got MAF.. The Corvette or any other GM car (other than your GTO) shows gallons per hour.
Originally Posted By: LS2JSTS
In my Holden/GTO the fuel used is measured/calculated somehow at the injector itself, iirc. Something to do with the ECM and the pulse width thats being sent to the injectors. The readout is very accurate and even switches from average mpg readout to gallons per hour when the engine is idling. None of my other GM's have had that ability...curious does your Corvette read GPH at idle Patman?