2003 discovery . 68k miles has developed a rotten egg smell at startup that seems to go away after its warmed up. Anyone know what this could be I imagine it has something to do with the cats but is there a way to prove it or test other things

 

You can chart your oxygen sensors if you want, upstream should be reading close to 1 v, downstream should be reading about .5 v.

 

Check your fuel purge valve if it sticks open it runs and smells like hell

 

I just replaced the purge valve with the Hyundai part

 

I read that wrong. I replaced the purge valve on top of the engine

 

sweet. Now more troubleshooting lol

 

What do you mean. Do you think I should still check out the fuel purge valve

 

could be other things but that was a problem i had which took forever to find, shop couldn't figure it out why my rig was running like crap with o2 codes everyday etc i eventually found it

 

I don’t think I’m getting any codes for that but I haven’t checked. Currently extending my rear abs wires to get rid of the three amigos so once I do that I’ll check the 02 monitoring like the previous post said and possibly replace the purge valve

 

Sounds like cooler/cold weather, rich starting conditions, and the catalyst system doing it's job to me.

I dunno how many vehicles I smell on a daily basis working on ATM/ITM's but I've smelled that same sulphur/rotten egg smell from brand new cars with paper plates so IMHO if you have no CEL or pending codes I wouldn't worry about it.