95 tracker fumes

I bought a 95 tracker off ebay in February. Runs great and fun to drive. Put O2 sensor in for inspection. Mechanic told me put a cat on it, doing that the end of month. My question is when going down hills I get fumes. Could this be because of the cat? Thanks.

I bought a 95 tracker off ebay in February. Runs great and fun to drive. Put O2 sensor in for inspection. Mechanic told me put a cat on it, doing that the end of month. My question is when going down hills I get fumes. Could this be because of the cat? Thanks.
could be.. is there any funes in the engine bay when its at operating temprature? Ebay has some cats on there. I bought one from SSautochrome or something like that.. Its cheap so dont expect it to last forever.heres a link 60 bucks.. alot cheaper than buying one from a smog place or a dealership.

Do you have to pass a sniffer test or just a visual inspection?

http://cgi.ebay.com/ebaymotors/MAGNAFLOW-Catalytic-Converter-Car-Sound-High-Flow-94109_W0QQcmdZViewItemQQcategoryZ33629QQitemZ79505 79561QQrdZ1QQsspagenameZWD1V

Had to go through the sniffer test. The only time I smell the fumes is when I'm going down a hill. None when sitting idling and I didn't notice any outside when it was running with the hood up if that's what you mean. It does have a slight miss when idling that they noticed at the garage.

Had to go through the sniffer test. The only time I smell the fumes is when I'm going down a hill. None when sitting idling and I didn't notice any outside when it was running with the hood up if that's what you mean. It does have a slight miss when idling that they noticed at the garage.
probably just a lack of CAT for the fumes.. E-mail the seller on EBAY if they will pass your states smog. I believe thay will pass california will def pass federal emissions. (you may have to advance or retard your timing a little. It also helps to burn 91-93 octane fuel burns cleaner.)