hello all just purchased a 1988 grand marquis in mint condition with only 83000 miles but i have one problem. The a/c works great as long as the car is idling but as soon as you accelerate it starts blowing hot air, and sometimes diverts to defrost or floor ducts. Also the same thing sometimes happens if you have the fan set to auto and the controls set to off it will blow hot air out of the floor duct until you idle the engine then it will turn off and upon accelerating it may stay off or may come back on. The only possible thing i can think of is maybe a vacuum leak for the blend door as ive read that these cars when equipped with the auto climate control which this one has have a vacuum actuator behind the glove box but i do not know if replacing this would help me or not thanks in advance for any help.