Catalytic Converter

I have a 2006 Impala LT 3.5 with 130k. I've done a full tune up but lately it seems like my mpg has dropped and i smell a rotten egg smell sometimes. I think the cat may be going bad but I have no cel on. Ideally I'd like to buy the magnaflow direct bolt in converter but money is an issue right now. I thought about gutting the cat but don't want the cel on. Does any company sell simulators and/or direct bolt in straight pipe? I'm looking for better performance and mpg.

don't alter the cat, it will be detected at the pollution inspection and a fine will be issued. if you still want to look for parts for off road / dirt track , they have all kinds of stuff like deleting the EGR from the PCM and a plate to fit the opening on the manifold when removed, then again if you get caught with a street legal car........

The smell you are getting is too rich a mixture not a cat issue, should do a full scan for a proper diagnosis.

Running rich is a great way to destroy your cat, as well as potentially setting your car on fire as it can cause the cat to get incredibly hot.

Reminds me of that company , out of business now, that made a kit that would turn off your ignition while the injectors still where pumping gas in. Then the ignition was switched back on and 6 foot flames would shoot out the exhaust pipes. I think the video is on YouTube. If I can digress for a moment reminds me of when my Dad took me to see one of the Chrysler turbine cars in 1964. They had one of those stands the hospitals use to hang plasma on for the patient. They had different fuels they hung on it from bourbon to rubbing alcohol the car ran on. The only drawback was the exhaust coming out the back was 1500 degrees.

Your smelling a rich exhaust which will eventually ruin your cat, if its not too late, I'd test/replace O2 sensors. You may have a dead O2.

I doubt a dead O2 sensor, the CE light would be on.....but it could be something that affects the pre O2 sensor like a vac leak, exhaust leak, or bad MAF....

Even though the CE light is not on, should still check for codes......may not have noticed it on....