Very bad exhaust smell

[alp]

When I first start the truck and keep it idling the exhaust smells stinkely of rotten eggs . Terrible smell! But after I drive the truck for a while and then stop it there is no any smell at all. I don't think it is normal and I look forward to hear from you guys your opinions and advices. Thanks.

 

[Rc4r]

Its your catalytic converter

 

[DH4Runner]

I too have an exhaust smell that's sometimes overwhelming. Mine really never goes away though.

Yeah, I know. That wasn't any help!

 

[01KY4R]

Its your catalytic converter

Bingo!!!

 

[alp]

Its your catalytic converter

Thanks for the opinion. But how to explain that the smell is completely going away after I drive my truck for awhile? Well, I am still trying to sell to myself that it can be O2 sensor. Is there any practical way to diagnose this problem rather than replacing the cat that I am trying to avoid for understandable reason? Thanks.

 

[Army]

It goes away, because the cat is now hot enough to burn off those vapors and particles you smell while it is still too cold.

It's normal.

Try different grades of gas to see if it helps any.

 

[Rc4r]

I couldn't tell you what causes it but in my parents 05 expedition had this problem and replacing it fixed the roten egg smell