'88 80Q AC Cooling Phenomenon

["mikesoft" <mikesoft@europa1.conwaycorp.net>]

The AC was recently fixed in my '88 80Q. I got a used
compressor along with a new receiver/dryer unit. I also
did a R-134 conversion. The strange thing about it is that
the car unlike most cars cools better when the car is
stationary and idling. The idle is erratic apparently due
to a cracked ISV hose that I plan to replace this week.
The cooling is ideal at idle with the REC switch depressed.
The minute the car starts moving say above 30mph the 
cooling reduces, quite frustrating on a 90+ degree day.
I would appreciate if someone could give me some insights
on what might be causing this. Thanks 

Mike Theuri
88 80Q