My air conditioner has just started acting up. It won't come on at idle and sometimes when I get on the road, it won't come on until I switch it off and on every couple of miles. When it does start cooling, it lasts the rest of the 60 mile commute home. Does this sound like the clutch malfunctioning? It's so busy in the oil patch here, I have an appointment at a local Firestone dealer a week from today to look at it. I'm at 151xxx miles now, with nothing done to the air conditioning.