I notice no real difference with or without a/c. Current tank, and I am driving a little easier to see what it will do, is 27.8 in town. Over 30 highway. A/ makes no difference. Sounds like you have a compressor problem. Mine still runs at 199-201 in Phoenix. Hot and humid today, 105 degrees. My a/c temp stays the same driving or stopped at LOOONG lights in Phoenix.