I've got a 2005 limited w/ rear air suspension. 130k miles. Some mornings, but not every morning...once or twice a week, the rear air bags will be empty and the back end is squatted down. Start her up, the compressor kicks on, airs them up to normal, and all is ok. The rest of the time, the other 5 or 6 days a week, its perfectly fine....right where it should be. I don't notice any problems with the ride, and don't suspect bad shocks at this point....but I don't rule anything out just yet. Has anyone experienced something similar? Trying to troubleshoot this. Thanks for any help.