Removing catalytic converters.

When I removed my cat and resonator from my car my computer got all wonky and ran way lean , one way i fixed the problem was to use richer fuel , but I got sick of using more money to make it run "normal" so I bought an O2 simulator to fix the problem it was a piggy back harness clip that went on the O2 sensor on the exhaust pipe. Now I run with mid grade gas and the hp and torque gains became very noticeable more noticeable than regular or premium. Now why would a muffler shop do custom work and not try to sell an O2 simulator so it runs good , did they want me to figure that out on my own?

They do not sell them b/c it’s unlawful to remove emissions devices. So I would guess they do not want to encourage that stuff and probably not a lot of business for that anyways.

By the way, you have a PM from me.