Lukas99GS

its only been doing this for the past month or two, and only if I floor it like at highway speeds to 80-90 mph, it goes away after a minute. I've heard a bad cat can do that but my mpg is still high ( can get about 28- 30 on highway consistently with 460) and there's no codes or warning lights, should I just live with it or is it anything to worry about?

guzzy92fs

Happens when using low quality gas. Did you recently switched to a new gas station?

From another post:
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​​​Run your current tank out as much as you feel comfortable...if you are ok with driving til the Low Fuel warning comes on, do so
Step 2. Switch back to your old gas station that you had no issues with.
Step 3. Repeat Step 1 approx. 2 to 3 times with your old gas station gas.
Step 4. Enjoy...your rotten egg smell is gone now

primavera

When was the last time you changed your transmission fluid?

Lukas99GS

Never has been since lexus keeps trying to say it doesn't need to be, but I'm going to make them do it regardless in the next few weeks.

guzzy92fs

What does the transmission fluid have to do with this smell??

TRD_Power

Honestly sounds like a cat on the way out.

primavera

Transmissions working under heavy load put enormous stress on the entire driveline of your vehicle. There is a fluid coupling inside the automatic transmission, inside the torque converter that is putting extremely heavy load on transmission fluid. That fluid temperature spikes way up and when it starts to get up above 250 aproaching 300 F, which is very easy for it to do in these high horse powered, high loads environments. Conventional transmission fluid simply starts to fall apart, it can not take that heat. It starts to vaporize, fall apart, it leaves behind a varnish, gum and sludge inside your transmission, which than starts to damage transmission parts, because bands and clutches are no longer lubricated and cooled. When the fluid falls apart because of heat then it creates even more heat and so very quickly you have permanent transmission damage. Overheated transmissions have very distinctive burning smell, when that happens it is your worst nightmare.

http://transmissionrepairguy.com/tra...n-overheating/

MX73

Transmission fluid doesn't produce a rotten egg smell. Even if you burn transmission fluid, it has a distinct sweet smell. Not as sweet as radiator fluid.

93SCMax

This...easiest thing to do 1st. If this doesn't cure it, start looking at the cat. Good luck!

sprtn131

This is pretty common on full throttle acceleration. You're basically dumping fuel into the engine, and when the excess hydrocarbons (fuel) react with the the cat it stinks. Happens on all cars. Especially if you don't go into WOT(wide open throttle) or heavy acceleration very often

Lukas99GS

I've heard other people with Lexus having that smell without a bad cat, what you're saying could be true, I used to drive fast all the time and never got it, but after I got the worst speeding ticket of my life last spring I don't floor it often anymore haha