I've got the same problem with my 87 5000cst. It's very annoying and I've been told normal. Is it just a very inefficient compressor; I haven't experienced this in another car. Even my girlfriend's old subaru doesn't act like this with the air on, and it only has 85 hp! My solution is to hit the "ECON" setting on the auto climate control when a hill's coming up. --Steve Brehm