I have a few questions about my 1996 Aurora

Love the car but I am about to get rid of it b/c of mileage and age. When I start the car inside (after running) i can here a kind of scrapping nosie coming from the heating ducks on the passenger side and the temp. blinks. The A/C is still cold. Also, after running for a while the car revs up and down(Sometimes so little it does not register on the tach and sometimes alot)

Thanks for any input AND YES I PROABALY AM GOING TO BUY ANOTHER AURORA.. LOVE EM.