gas mpg

Just installed Titan motorsport catless downpipe with generic 02 sensor CEL spacer. Also run a Dinan stage 1 controller. Noticing a slight decrease in MPG, is that common? I know the obvious catless means no restriction which means less work on the engine to produce more performance. And MPG...

The EPA's FuelEconomy.gov has just listed 2020 Supra 6-cylinder and it gets 24 mpg city, 31 mpg highway and 26 mpg combined! Impressive figures considering the four-cylinder BMW Z4 only gets one more city and highway mpg and two more combined mpg, but down down 80hp / 70 lb-ft compared to the 6...