I have a 2001 LS 430 with 113k miles all season tires and I use 93 premium gas but i get it from the Costco gas station. If you dont know what Costco is it is similar to Sams Club. When accelerating to about 3000 or more rpm there is a rotten egg smell that comes into the car. My grandfather who used to work on cars says it could be from the "cheap Costco" gas that I get but I feel like it could be my Catalytic Converter that is causing the smell.

 

Ya thats usually synonymous with bad cats.

 

Would Catalytic Converter Cleaner solve this problem?

 

Do you have any check engine codes displaying?

You could have cracks in your Y pipe. You have a front passenger and front drivers Catalytic Converter. Then there is a rear Cat. Most problems happen with the front pair.

You should be getting a P0420 and P0430 codes thrown. That could be the converters or the cracks in the Y pipe.

 

A while ago I got a evap code P0440 but I was recommended that it was a gas cap issue and it was resolved with the gas cap. No other engine codes. Every once in a while i do get an air filter warning but I just got that changed a few months ago

 

Agreed that your odor is most likely from bad cats but in addition you may want to reconsider the advice that Grandpops gave you about the quality of Costco Gas. It is considered Top Tier and you can read about it below.

https://www.costcoauto.com/automotiv...gas_nozip.aspx

 

I use Costco gas in my 2015 X5 and I've only filled up once since I got the LS, but that was also costco.

 

 

My 01 did it too under hard acceleration. Seems to be a standard early LS problem. I closed the sunroof. End of problem.

 

My 2005 LS 430 Rotten Egg Smell When Accelerating has been a constant normalcy for the 10 years of ownership. I recall taken my car to the dealer when it was under warranty and being told that all is well.

 

Zero problem w/ my 04 in 20k miles.