On all the 123 Cars.. if you have an air intake near the speaker on the passenger side.. or one in the center of the dash.. You will get just what you fellows are talking about if the foam section of pipe from the air intake has gone to heck... Pull the glove compartment and check the pipe running from the intake to the heater blower.. If the foam section has gone bad.... drop by your local hardware store and pick up some pipe insulation for 1/2 inch copper.. it will be about 3/4 inch inside.. cut a piece and put the two ends of the plastic tube back together with the foam.. That often solves the problem you are talking about.. If thats not it... Good luck..

Ken