The autometer gauge works off the cars own O2 sensor, these are designed to only work in a very narrow band. To get a REAL idea of where A/F is you need a wideband O2 sensor.RGrossman said:I have the PRedator and I'd like some reassurance of where my air/fuel ratio currently is. On the Autometer air/fuel ratio guage, is green like 12.5 and below? does anyone know where green ends and stoich picks up? Just trying to get a quick reading.