I've read where idle should be 750rpm.Is it 750 in park or gear or both. Seems when in gear mine is lower than 750 and more like 600 when fully warmed up.Is this condition proper. As far as the BAC is concerned when the a/c is turned on and the engine hood is up should you hear the BAC make a clicking sound? If it makes a clicking sound does that automatically mean it is working properly or can it click but still not have the correct resistance? Lastly,lately when I have removed the gas cap I have noticed a vacuum sound(rush of air) that is fairly strong and loud and lasts for 3-4 seconds.Is this proper for it doesn't do it always, just here and there.I have used some injector cleaner recently called "Sea Foam" and wonder if this is causing the vacuum sound.Thanks and have a great day!