Rotten egg smell 2012 Taco 72K

No engine light or codes. Bad smell after freeway speeds in slow driving and down long hills under no acceleration at freeway speeds. My first thought was a bad catalytic converter, but there are four of them. Do the front ones go out first? How do you know which one is bad?

I've also been told that a clogged fuel screen in the tank or a bad fuel pressure regulator can cause this. Any clues on diagnosing?

I've contacted the dealer and since the truck has a salvage title they say the 80K warranty is invalidated on the cats. Is that true?

 

Thanks, nice to see and be able to mine the brains of people with experience. I'll add what I know as I can.

 

Differential oil smells like spoiled eggs. I'd check levels and for leaking at your axles.

 

From my experience bad o2 causing rich condition and then builds sulfer in the cats. Did you drive with bad o2 and then had it replaced?

 

No codes... Wouldn't a problem O2 sensor set a code?

 

Welcome to TW...Hope you get it figured out!!

 

Welcome!

 

Welcome to TacomaWorld!

 

Usually yes and I was asking if you ever had to replace the o2 previously in your ownership.

 

Welcome to TW!

 

I just got the truck at an auction. It was rear ended and I had to do some frame work and replace a few parts. So I have no history on the truck other than knowing it was owned by a city utility.
I went for a long drive over the last couple of days and had no smell. Prior to that I'd put some Seafoam in at half a tank and run it down to less than a quarter tank. Maybe I'm good? I guess we'll see.