i think it might be this vacuum pump is loose and somehow causes vacuum leak. i can't find reference to a vacuum pump back there but its not often enough to be the fule pump. it runs for a couple of seconds every 20 mins.
I just bought a 2004 Buick Lesabre custom, beautiful car. When I start the car I hear noise coming from the back (trunk area? last about a minute then goes away (sounds almost like a compressor). It may also come on later while I'm driving, the dealer said it's the air suspension. Not sure about that, does anyone out there have similar experience????
Thank you, it will make me feel better if someone else has the same issue and hopefully it's "normal".