A while ago I posted about a problem with rotten egg smell. It was not the CAT but I changed the Heated O2 sensor and that cured the problem. Also, my gas mileage improved. I have just under 70K miles on my 94 GXE.

I used the factory OEM sensor. $114.

On recent highway trip mileage - I got just over 32 MPG. 300 mile trip on open highway driving (60-70 MPH).

Also, FYI I run Mobil 1 5W-30 oil, Mobil 1 ATF, Michelin X-One tires. Vehicle is stock.