AFAIK, there is no cabin filter in the 97.
(If there is, then mine must be in reeeeaaaly bad shape!)
(If there is, then mine must be in reeeeaaaly bad shape!)
If the previous owner smoked, the tar will stick to everything. If he used the fan in Recirc mode a lot, it will coat the inside of vent tubes and will send that smell out when warm or when a lot of air flows across it.
If the AC was used a lot, the moisture left in the lines can mold/mildew a bit and be a pain to get rid of the smell. It's recommended to run the fan for 5 minutes with no AC after running the AC for a while to help dissipate the moisture.