do they sell o2 simulators or somthing like them so that you can clear your cat without throwing any codes? also did you feel a big difference when you cleared your cat?? thanks

 

defcon-racing.com sells an 02 simulator, when i cleared my cat it did make a difference to the gas mileage(real shitty). all it is the 02 for the cat isn't plugged in and is not reading any readings for that 02 sensor, so it throws off the computer and messes up your gas mileage.