Hey guys, My 07 Denali will cycle the compressor at startup, but then after it runs it then shortly after starts letting air out. When I hear the very faint sound of it releasing pressure it will stop as soon as I push down on the bumper. So the valve is working properly. Why is it letting...

I am having a problem with my headliner in my '07 TB LT. Behind the sunroof, where the dome light is, the headliner keeps sagging/dropping down. I can push up on it and it will stay for about a minute and then I can hear the "velcro" releasing and it drops back down. It is only dropping about...