It's the gas that you put in. Like mentioned above try switching gas stations. That smell comes from low octane gas. It happened to me from time to time but once good gas is put in then it goes away.

 

that gas stuff doesnt make sense, its the cat or something in front overwhelming it. Look up rotten egg exhaust on google.

if it was fuel then lots of other cars would stink, but that isnt true is it?

 

its normal for that smell to happen. that means ur Catalytic converters are working properly. again, its normal.

 

im gonna bump this for my brother.

he has an 04' 430 with 108 K miles, but I understand the smell when fully flooring it. But in his case he gets it when he even hits 3K RPMS. very frequently he gets the smell and he's annoyed by it, and I would be if I was him too. Any suggestions?

 

make sure you have enough water in radator and maybe change gas octane or brand.

 

Another vote for better gas, make sure to use 93 octane

 

my brother has always used 93 octane and has changed gas brand several times

 

Tell your brother to get his 02 sensors or cats look at. I had bad smell before but engine light to it was 02 sensor in rear. My light is back on and smell when floored p0420 code bad cat. The cause of my cat going bad was I had a bad fuel injector and drove to long with it bad.

 

I am still getting the smell at the 3K and above. It smells like rotten eggs. Its NOT the gas, I use 93 every time and have tried different brands since posting this thread. It cant be the fuel injectors. How can it be the O2 sensors? they're just sensors...It has to be the cats.

I go in for an alignment Saturday, ill ask around

 

I don't believe the smell of rotten eggs in an LS430 (or any model for that matter) is normal. Have never had that smell in any Lexus I have had or driven as loaners when mine is being serviced.

Definitely something wrong.

 

if it smells like rotten eggs then its your cat. they are going bad

 

Nope, that is wrong. The smell means the catalytic converter is doing it's job. I started using Shell V-Power and I've noticed the smell recently, but only when I'm giving the car a decent amount of hell (Above average acceleration, cold starts). I switched to BP and ran an experiment (Cold Start, long periods of heavy acceleration) in an empty parking lot... no more sulfer / rotton egg smell.

I also tested the Shell fuel in my Frontier, and even driving in normal conditions, the moment I get out of the truck I smell a mild odor of sulfur. My Frontier only has 22,000 miles on it... which means that is is highly unlikely that a catalytic converter can be going bad.

I've been using Speedway Fuel for the past several fill-ups with an odorless exhaust... I'm beginning to wonder if A.) Shell has cut refining costs, reducing quality of fuel (More sulfur) or B.) Some Shell stores are actually not using Shell Gasoline, and are somehow getting away with it.

 

^I've been using Shell V-power ever since I got the car last Aug and have never noticed the smell.

 

Here's a Lexus TSB published in 2003 that talks about sulfur smell...

"TSIB EG001-03 (All Models): Sulfur Odor From Exhaust:

Some owners of Lexus vehicles may experience a sulfur–like or “rotten egg” odor from the exhaust system. Sulfur is a natural component of crude oil from which gasoline is refined and the amount of sulfur can be decreased through the refining process. The amount of sulfur in fuel sold in California is regulated, however gasoline sold in other states can have substantially higher sulfur content. Sulfur content also varies considerably between gasoline brands and locations."

 

Here's another TSB specific to 2006 IS250 / IS350 vehicles... The reference in it at the bottom refers to my previous post about gas quality / refinement...

"TSIB EG017-06 ('06 IS250/350): Excessive Sulfur Odor:

Some customers may complain of excessive sulfur odor on 2006 model year IS 250 and IS 350 vehicles under the following conditions:

-Stop and go driving
-Heavy acceleration

In order to reduce the sulfur odor, a new catalytic converter assembly has been made available. Follow the repair procedure to replace the catalytic converter assembly.

NOTE:
-For more complete understanding of the root cause, refer to TSIB No. EG001–03, “Sulfur Odor from Exhaust.”"