AC issue

This is a Gen 3 (2006 FE coupe).

This situation first happened last weekend. Traveling some back roads in my area with many stops, etc. Temp outside was 95F+ (heat index >100F). Starting the drive, the AC was performing perfectly. super cold air, all 4 blower speeds working fine. After about 45 minutes, started getting warm inside, turned blower on high (level 4, recirculate). Blower motor was definitely working fine (on all speeds) but instead of full air velocity coming out of the front vents, the airflow was very restricted but I could hear what I believe was a lot of air being redirected behind the dash.. but again very little air blowing out of the front vents. Also the air at that point was no longer super cold as before.
The next morning, I tested the AC, and it was blowing super cold air at full velocity out of the front vents as expected. Everything was back to normal.

To note: end of last year, I had to replace the blower motor and have not had any issue with the motor since (i.e. all 4 speeds work fine). Also, after last weekend, I replaced the blower motor resistor (that was this past Thursday) just to make sure it was not causing the issue I had last weekend.

Then yesterday (Saturday) I did another road trip on some back roads again. Outside temp was 97F (heat index 104F). Like last weekend’s trip, the AC started out fine, super cold air, full velocity blowing out of front vents. Again, I’m guessing an hour into the trip, the air flow became reduced, no longer super cold and again I hear a lot of air blowing behind the dash.
My wife and I stopped for lunch. When returning to the car (about an 1.5 hour later, the AC had returned to normal, blowing super cold air, full velocity from the front vents. Stayed this way the remainder of my drive back home (about 25 minutes via all highway).
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So.. poking around on the forum, I’m thinking this could possibly be a vacuum leak where the blender door(s) are affected? I’d very much like to know your expert opinion on what could be causing my AC issue. Seems it’s when the engine heats up.. but then when it cools back down, the AC issue goes away.

Thanks in advance!
Dwayne

’06 FE coupe