93 firebird gas smell

[dosdonkey]

i have a 93 firebird and it was recently serviced after sitting a year due to rabbits chewing up the wires! it still feels like it runs a little rough and there is a vibration when at idle in every gear but i think it might be the cat. since the vibr sound like it could come from there. the car also has a heater problem it doenst get hot and the temp gauge show the car to not get warmed up past 160 or so either i listened to the fans and they seem to come on at weird times even after i first start the car, does the rough idling and gas smell sound like the cat? and what could cause the heater fproblem? and its and lt1. i also unplugged the fan fuse and the motor heated up fine but the heater is still cold not hot at all.
it also wont blow out of the vents only the defrost no matter waht the setting i wonder if its somehow stuck on ac defrost? but it lets me turn it off and on