Okay, someone has had to have the same issue. About once a month I will got to my Hummer after its been sitting for awhile (sometimes over night) and it will be sitting *** low...the air suspension drained out. As soon as I start it up, the pump kicks in and its back to normal. Then it will be fine for a month or so. So can anyone tell me what the heck is going on and how do I fix it.

 

Sounds like an air bag leaking, air bags can act strange and some days leak and other times not leak. I would get under there with a flashlight and a spray bottle with some real soapy water and see if you can find the leak by watching for bubbles.

 

Any idea what that would set me back to replace?