The past week or so I notice when I get out of my car a rotten egg smell.. my car has 82k on it with stock exhaust.. I don't have any dash lights on and my car seems to be running all right but my miles per gas tank seem like its getting shitty.. could my cats be going bad?? What could it be??

 

Your cats are most likely whats causing this. How bad of a mileage decrease? Have your driving styles been similar? I would probably just run them until a check engine light goes.

It could also be some eggs you left sitting out by your car too

 

When I fill up I will keep track.. yeah I drive the same 95% of the time.. I just cleaned my intake filter cause it was filthy..

 

...

 

Step 1: Check if shoes are properly secured.
Step 2: If they are not, proceed to take one off and sniff.
Step 3: If you notice an egg like smell, wash yo feet!

 

If its my cats it gives me an excuse to get motordyne art pipes and xyz with high flow cat..

 

I just washed my feet so I'm good there!!

 

I think its your cats, but thats my opinion.

 

Bad cats will give off a sulfur/rotten egg smell. Most likely it's your cats.

 

It's the cat between his legs...

 

Haven't smelled it lately.. so I guess I'm good for now.. lol

 

Older/cheaper cats used to do this anyway under load, the new ones still do, but only under load, it's a sweeter smell nowadays,




This is where it's at


There's every chance that they have started breaking down, i'm assuming your intake cleaning was done after this? or have you just start noticing this since the cleaning?

 

Rotten Egg smell from Cat's is often due to something else , not the converters. Thiers no external air pipe so the flow thru cats maybe the issue. OEM cats with F/I will break apart and could possibly clog anything downstream in exh like resonators or mufflers.

Determine If its more noticeable under heavy loading (boost or uphill). Not sure if your boosted but it will be more challenging assuming your tuned richer. Spark plugs will tend to start fouling up if exhaust is clogged.

 

As i said, cats used to smell like that from the factory, just not so much these days.

It's quite possible something has gone through them, causing the smell, like excess chemicals from cleaning the intake.

 

I cleaned the filter after I smelled it.. what happened was I pulled up to my buddies house and got out of the car and the smell hit me but I haven't noticed again..