I removed the catalysts from the catalytic converters, my engine is still running poorly and still has the P0420 error. Why?
Hello! I have a 2000 Toyota Avalon XL with 164,000 miles and an automatic transmission. I bought this from a private party approximately 3 years ago. I've had issues with the catalytic converters, and after using a couple of methods to prolong their life, they were finally done for. Unfortunately, since catalytic converters are quite expensive, I ended up just removing the catalysts. It didn't seem to help. Some days it drives pretty good, other days it shakes violently and sounds like it's about to break down, just as it did before I removed the catalysts. The blinking "Check Engine" light is anxiety inducing and happens sometimes. It definitely seems like it's misfiring, and to be honest, I'm not really knowledgeable about vehicles. I'm thinking that the O2 sensor is sensing there's still a problem. The sensors were made to regulate that area of the car and it's missing a catalyst, so it may send errors to the computer and cause the engine to run poorly. I know the best option is to buy new catalytic converters. I just would like to know if there's a way to fix it without having to buy and install another catalytic converter. I truly appreciate any advice anyone can give me. Thank you.
The blinking "Check Engine" light is anxiety inducing and happens sometimes. It definitely seems like it's misfiring
The blinking "Check Engine" light is telling you to stop driving ASAP to avoid engine damage.
That car is nearly a quarter century old, the problem could be caused by almost anything - as simple as filters or spark plugs, or as serious as bad compression. You need to do some diagnostics before throwing parts at it. Getting an inexpensive scan tool to check for codes and data such as fuel trims would be a good start. See the site FAQ section on diagnosing check engine light and misfires.
Of course it's illegal to remove the catalyst from here systems, but it won't affect the running of the car. It's strictly an anti-pollution device
