re: Catalytic converter question…

For GM vehicles (Chev Equinox & GMC Terrain is what we've seen the most) with catalytic converter codes I recommend using BG 44K that you can purchase from Amazon. We used this many times and I can only think of 3 vehicles where this didn't work...and that was due to the system being totally blocked and all exhaust being pushed back thru to the engine. So if you try this early on and before you reach the point of total restriction you should have no more issues for a while. Then I would add a can every 20-25k miles at fill-up.

Pour (2 cans) of it in your fuel tank and then fill up. This stuff really helps burn off carbon build-up on internal valves/pistons; fuel injectors and burns the carbon build-up in exhaust(Cats). The longer the product remains in your fuel system, the better.

Some vehicles may exhibit a rough idle (depending on mileage) after mixing however it has not affected performance (acceleration) under load. The "rough idle" is an indicator that its doing the job of dissolving the carbon and cleaning the fuel delivery and exhaust system.

BG 43K via Amazon