09IS250RWD

My '09 IS 250 gets a real bad egg smell if I'm hard on the throttle. I only run 91 octane or 94 sometimes. I've also put seafoam in the gas, oil, and vacuum hose to clear up any carbon deposits ...It's still making the smell.

skullkandy

The smell is sulfer from your catalytic converter.

Unless you get new cats or a whole new exhaust system, you won't be able to fix it.

09IS250RWD

Okay thanks. I figured it was bunged up cats, but I thought they would eventually burn all the crap out of them...

09IS250RWD

How does this happen by the way?

Eduskator

Not an expert, but my guess is that the sulfur escapes somewhere in the exhaust process. Your exhaust need a lot of ''flow'' under hard acceleration (burnt fuel travelling a lot faster) and if cats are clogged, it might stuck and escape under your floor at some point?

Correct me if I'm wrong, but your cats are still under original warranty I believe (8 years / 80k). Might want to have Lexus check them ASAP

Gville350

iTrader: (10)

Get cat-less PPE headers and an aftermarket midpipe; that's solve the problem. LOL!

Does FL still not have emissions testing?

MistaMiagy

i've replaced all the cats and i still have the problem of bad egg smell when i push the gas to the floor. So on the next week i'm going to get the engine and transmission box down in order to replace the gasket of exhaust manifold on the engine block.
This is the last thing i assume can have an issue. If the problem still exist i'ma burning my vehicle to hell.....!!!!

hshviak

I had the same problem. I looked everywhere to find a solution but mostly ended up with the catalytic converter problem. The thing is that whether the catalytic converter is healthy or not, the smell shouldn't come inside the cabin which led me to an exhaust leakage problem. exhaust band clamps almost tend to leak especially on hard acceleration when the pressure goes up significantly. Long story short, I sealed up the exhaust band clamps before the muffler, and guess what the smell completely went away. The clamps were almost close to tailgate and I wasn't so optimistic that it could solve the problem but hopefully, it did. you can watch the video of this dude to find out how to seal the clamps:

You Tube

Akai00

Happens on my car when the A/C is on. From another poster on this topic:

"It's your AC. I am assuming you are running your AC while you are performing these runs. When you WOT, your A/C turns off. This causes the egg smell. Do a test. Turn on the car and the air conditioning. Then turn off the A/C condenser. See if you get the smell."

Akai00

Replacing the exhaust manifold gasket seems like a waste of time. From what I've gathered this is a common problem and relates to your A/C not a malfunctioning CAT, gaskets, etc. I could be wrong though.

Dealarr

Your problem might be the joint's between the mid pipe and the cats, it is built in such ways, that it is EASILY leaked if you don't have an exhaust flange on it. Almost feels like sabotage, anyway, if your joints are mid pipe to catalytic converter with nothing in between.

If you suspect your headers maybe leaking, which isn't too shocking. If you all notice, our exhaust pipes hangs by the headers, there are no hangers or supports except for a flimsy bracket which goes between the tranny and engine. Get a 12mm deep socket to tighten the top screws of headers off, it's the top screws they are pulling on. Hence ISF gets cracked pipes, i have engineered a bar which will support the exhaust abit better will put up pictures later.