I have an 08 with 85k. All stock except joez Intake. Last night I had a strong rotten egg smel after doing a short WOT pull from about 40-70. I know this smell has to do with the cats but does this mean something is needing to be replaced or is this a build up that goes away if it push the car more? I tried it again a few hours later and got a sorta burning smell that I've had once before but no eggs that time.

Aside from needing to drop a full headers and exhaust system in what should I do?

 

I'm not sure if it makes a difference, but my F did the same thing after sitting for awhile. I recently installed full exhaust (w/ no cats) and it smells worse than before so I ordered some hi flow cats that I hope will resolve the rotten egg issue. I will let you know

 

Supposably it has to do with carbon build up in the headers/primary cats. I removed my mufflers and it went away for a while and wasn't as strong now I only get it when I do a bunch of pulls or keep it in high rpm under load. Mine had around 85-90k on it when happened.

 

It's normal. Sulfur (SO3) builds up on the catalytic converters during rich conditions and then that is released when WOT with leaner conditions (hotter exhaust gas temps.) heat the plates up in the cats to catalyzing temperatures. What you're smelling is hydrogen sulfide (H2S) and it'a actually a sign that you're emissions system is operating at a highly efficient level.

 

Gasoline currently doesn't have sulfur limits like low sulfur diesel does... the smell is normal as stated above.

 

Yep mine does it (Lexus says its normal)but if you flog it a few time it stops, plenty of threads on this and have a look on gooooogle cheers.

 

Constantly push the car more and the smell will go away.

 

EPA does limit sulfur content. Tier III is 10 ppm.

 

Here you go:
https://www.clublexus.com/forums/is-...ot-solved.html

Instead of taping these up, I would try to purchase new parts first.
I've been thinking about this post for the last few weeks as since the temperatures drop, I've been smelling this more than usual since I've had this car for the past 3 years.

 

Pretty common to have that smell in a car that has factory catalytic converters.

 

is tier 3 in effect already?
smaller refineries such as the one I work at have an exemption until I believe 2019. Gas we ship out has 60-80 ppm of sulfur.

 

Ive been noticing it during cold temps also, any reason why its much more obvious when its cold out?

 

Tired of the smell, remove the cats!

 

Denser air, leaner conditions, increased exhaust gas temperatures.