you have a missfire in the motor and raw fuel is contaminating the cat converter. get it checked out before you damage the cat and require replacing it.

Roy

I have a 2004 srx with the same problem I've scan the code and got p301 also i know that that mean misfire cylinder 1 I've tested the all coils and found cylinder 3 open what do i do next i don't want to was money on this i have also replaced both down stream o2 senors about two months ago

Hello,

Yep this is not a o2 sensor problem at all. Replace the open coil which will cause the problem. When a cylinder misfires it causes the system to go lean which the computer will richen up causing the rotten egg smell.

Please let us know what happens

Cheers, Ken