My 94 LWB air susp. is going crazy. It is cold in Mass. and the susp is acting up. some times the front susp drops when it parked and other times it is the rear or one side or the other. It is taking time to rise to driving level. I hear the pump and it stops before driving level. sometimes I hear a release of air as if susp is full and level when it isn't. The susp is a driving level, I shut the truck off and open the door, susp stays, I close the door and that then system will immediately drop to the bottom or it will be the front ,back or a side????Any ideas what would cause this??? Rick