Rotten egg smell WOT

[MachNroll]

I have a 21 Mach 1 with 12,000 miles on it. Only mod is a resonator delete and add x-pipe. I run Chevron 91. Recently I've noticed a rotten egg type smell after WOT or driving in second gear at around 2300 RPMs (like rolling thru traffic jam or parking lot). Check engine light has not come on. I used the search on this forum and saw various related posts, but nothing was definitive like someone took their car with similar symptoms to a dealer and X was done/diagnosed. So, posting now to see if I can get a more definitive determination as to what I am smelling to help me with next steps, including if deleting the resonator and adding an x-pipe could be the problem. Thanks all for any feedback or suggestions.

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[Zrussian13]

Probably your cats. Search cat over temp protection. I used to get that smell after hard 3rd gear pulls. Totally normal.

 

[MachNroll]

Probably your cats. Search cat over temp protection. I used to get that smell after hard 3rd gear pulls. Totally normal.

Thank you for the info... never heard of COT protection being called this. Learned something new today... I just have been reading alot about rotten egg/sulfur equals fried cats.

 

[Zrussian13]

Thank you for the info... never heard of COT protection being called this. Learned something new today... I just have been reading alot about rotten egg/sulfur equals fried cats.

If your not boosted you haven't fried your cats but I can see where the worry would come in after searching the forums! Before I went boost when anyone walked in my garage after I got home they always asked "why's it smell like burn rubber and rotten eggs in here?" Well obviously it's because I drive the mustang the way it was designed to be driven! Fyi I have almost 75k miles on my car now and it runs like a champ. Enjoy it, drive it hard and don't sweat the sounds or smells it makes sometimes. Those things can drive you crazy.

 

[MachNroll]

If your not boosted you haven't fried your cats but I can see where the worry would come in after searching the forums! Before I went boost when anyone walked in my garage after I got home they always asked "why's it smell like burn rubber and rotten eggs in here?" Well obviously it's because I drive the mustang the way it was designed to be driven! Fyi I have almost 75k miles on my car now and it runs like a champ. Enjoy it, drive it hard and don't sweat the sounds or smells it makes sometimes. Those things can drive you crazy.

Thanks! I took it to the dealer this morning for a looksee... all aok. There is a bulletin of some sort via Ford that addresses this issue. Common for these cars when new or newish to have an odor from the cats until they are seasoned/really broken in.

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