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[Solved] ATS fuel cleaner fixed the sulfur smell in my 2006 Tundra


Topic starter

I purchased an 06 Tundra V8 with 96k miles a couple months ago and so far it's been a great truck. I'm still learning the quirks and idiosyncrasies of my vehicle, but there is one problem that's been bothering me. About a month ago, I started noticing a rotten egg or sulfur like smell after getting out of the vehicle. The odor seems to be the most pungent right after I turn off the engine and get outta the vehicle.

The existing battery was kinda old, so I replaced it thinking the smell could be leaking sulfur dioxide from the battery. It hasn't fixed the problem. I also ran some BG 44k fuel system cleaner and so far the smell seems to have decreased by a fair amount, but more driving will give me a better idea. There are no CEL's on the truck at all and the fuel trim is +/- 1%, so the engine seems to be running great.

Could the catalytic converters being going bad? Not sure what else it could be, but there's no data from the computer to indicate that the cats are not running efficiently.

5 Answers
Topic starter

Bringing this thread back from the dead, but I wanted to share some results...

I followed Scotty's advice and ran some lacquer thinner in half a tank of gas, and afterwards I noticed the sulfur smell was not as potent. Definitely an improvement, but still not ideal.

Scotty also uploaded a few videos promoting the ATS fuel and oil cleaners. I figured what the hell, might as well try out the fuel cleaner. Was rather expensive for the combo, but shortly after I finished my tank of gas with the ATS fuel cleaner in it, I realized there wasn't any nasty smell. That ATS fuel cleaner is some fantastic stuff and actually worked, so it definitely is worth a shameless plug! Now I can roll around in the Tundra without squeezing my nose after getting outta the truck.

Thanks a lot for posting back with the fix. Well done!


Likely your cats are the source of your sulfur smell (likely why it was sold). But instead of just throwing new cats on, still need to figure out what is the cause. There are a number of things that could lead to the cats not functioning properly, incorrect timing, bad spark plugs, a malfunctioning oxygen sensor just to name a few. Find a good shop to diagnose/fix it. 


Did some research.  It's the oxygen sensors. The 2 upstream of the cat converters between the engine and converters need replaced.  The downstream sensors rarely go bad. Here is what I found.

Bad gas mileage and rotten egg smell

If a bad oxygen sensor disrupts the air to fuel ratio mixture, or too much fuel is injected into the engine, your vehicle's gas mileage will be reduced. This excess fuel in the engine can produce a sulfuric, rotten egg smell, and may even produce black smoke from the exhaust.


I would replace all the O2 or oxygen sensors with Denso sensors.  I own a 2000 tundra since new for 22 years. 300k miles still running daily driver. The oxygen sensors fail quite often.  I own a 2007 or second generation Tundra.  The oxygen sensors never fail. My neighbor owns a first generation Tundra.  He replaced all his oxygen sensors and his issues similar to yours went away. I bet someone put crappie cheap after market oxygen sensors in it. Might be cats but I doubt it. My 22 year old Tundra has original cats. No issues.  My bet is both upstream o2 sensors.  I'd just replace them all. 

Thanks for the recommendation! Before you replaced the O2 sensors in your Tundra, did you have any CELs ? Currently my truck doesn't have any trouble codes and I've looked at the live data and all the O2 sensors have the normal voltage fluctuation as I give it more or less throttle. I hope this is the cause of the sulfur smell because it's really annoying and is quite a negative feature on an otherwise awesome truck.

Yes, I had check engine light when they went bad. But they can also come loose. That messes up the sensor readings to the fuel mixture. Often people put cheap ones back. I only use the Denso sensors. I buy at napa. My neighbor changed all 4 sensors in his and got better mileage. It might need a fuel induction service cleaning. I run fuel cleaner through mine every oil change.

I ran a bottle of BG 44k fuel cleaner through it recently and presume it's too early to tell if it really made a difference. What's even stranger is that the sulfur odor seems to be the strongest a few seconds after I shut off the engine and get outta the truck. I don't really smell it if I'm sitting a red light with the window down.


BG is great stuff. I use BG all the time all my cars.