My 03 SC430 has 95000 miles on it and I notice on heavy acceleration I get the rotten egg smell.
I have no codes showing. Since there are 2 of these is there anyway to tell which one is failing.
No smell when driving normal speed. Next has anyone replaced these themselves.
Thanks
Theazz

 

I have an '02 with 68k and can smell the same thing from time to time...this smell will show up from any car.
It is normal and the hotter the day and hotter the engine/exhaust the more it will smell.

 

I agree this seems to be normal. You can also clean your cats with seafoam by running it through a vacuum line..

 

There was ~91,000 miles on my SC430 when the CEL P0420 came on. No bad smells prior to the light. The previous owner replaced the up-stream O2 sensor on that side to no avail ( so he covertly cleared the light with a hand scanner ( several times ) and sold the car to me, but that is another story...). There are actually 3 catalytic converters in the SC430. One on each side just after the exhaust manifold and the rear cat after the two sides combine into one pipe. The P0420 indicates the drivers side ( Bank 1 ) is inefficient and I replaced that catalytic converter to fix / clear the problem.

Without any CEL codes to guide you, replacing the converters would be an expensive trial and error process. Lexus actually wants to replace the bad front and the rear cat ( total $4,500 ) with the P0420 code. I chose to get a quality after-market Bank 1 cat and do it myself. Having a lift makes the job much easier. You will need to drop the Y center pipe with the center cat down to remove the front cat. While the replacement cat comes with the gaskets, you should stop by a dealer to get the manifold nuts and the rear bolts & nuts ( $6 a nut...).

Personally, I would live with the smell until a CEL light came on. Additionally, I would do a complete tune-up on the engine to eliminate any possible issues there. Things like air filter, spark plugs, PCV valve, throttle body cleaning, Mass Air sensor cleaning, checking all vacuum lines, etc. Plus a can of SeaFoam in the gas with the next fill-up.

 

Chevron Techron is my favorite, they add this to their fuel and it cleans the system well.

After running this through the gas tank, it actually reduced the smell, I also sprayed the throttle body out with CRC throttle body cleaner and I changed the PCV valve, $5.

Tune ups will make the car run nice!

 

So when do you get it back Bgw?

 

LoL, what do you mean my friend?

 

Have you gotten your car back from the mechanic?

 

Hey Harold, yes I have the car back and it handles Fantastic!!!

I did notice a leaking radiator but that has nothing to do with the suspension...

 

Glad the renovations turned out well.

I guess our cars are getting to the point where failures are starting to occur just due to age, not just wear. Bummer. Oh well, if we stay on top of it, they should last for a long time (at least that is what I'm counting on!).