Weird air suspension issue

[dna]

Had a problem with my air suspension on my 03 H2 for a few months now. Basically almost every morning the rear is sagging all the way down. Once I start the truck and hit height control the compressor raises back to normal height at which time it stays that way until again I shut it off. While driving I do not hear the compressor constantly cycling leading me to believe I do not have a bag or line leak. Also the rear only sags when parked in the normal height position. If I raise truck to max and park that way, the bags hold and never let go - they only leak when on normal height. Again leading me to believe no actual leak in the bags or lines. Sometimes I hear the air releasing a few seconds after turning off engine - again it is weird since it only starts to leak when engine off.

Heard it could be a programming issue on the early 03's, so I had the program updated today. Made no difference.

Any ideas.

BTW - if I need a new compressor I've heard the single stage (used in 03) is discontinued. If I find a good used one, what would be a fair price?? Anyone got one??

Thanks