http://www.ackits.com/aacf/ptchart.cfm
Test these at high idle.
Make sure you have no bad vac pods, a dead center pod keeps the defroster pod from fully closing which shuts the center vent flapper door...
Freeze 12 sucks in these cars in the city. Works fine freeway. Cost of R12 is not bad at all if you look hard and buy it off season.