ok so since its gotten colder, my car has been acting up alot lately. tps is dead again (already replaced it once), could it be the cold because it only happens when it is cold. i am going to rebuild it soon (1 1/2 weeks) but i'd like to have an idea what might be wrong with my car. lately, my exhaust note is getting deeper and deeper. its actually really nice now, the deep tone, but it never was deep. it used to be a middlish-low rumble/rattle. it actually makes alarms come on now when i pass by. cat is hollowing out/bad cat (cali car)? something else with my motor? i know i have bad oil seals and consume oil like a leech but could it be something else that may be causing it?