Nissan recently replaced my alternator. It cost me a total of $750....! Anyways, since then i smell gas or exhaust when i warm up the car. Also, my AC doesnt cool. The blower works but it never gets cool. Also, where i used to feel the drain on my engine when i turned on the AC,, now i dont feel that power drain. i assume that means its not working under the hood?.. Are these symptons related?..