Check, the vacuum. Had almost the same problem but it was when I hooked the vacuum line to the heater controls. A/c cars are vaccum operated and have lots of places where they can leak. Also check the modulating valve on the tranny, If you pull the vaccum line off that and its wet the diaphram could be shot. My two cents. Let us know what is was when you fix it so I can add it to my what to try list. Merry X-Mass Ron Hein