MIne has guage under driver(outside compartment) and it says normal pressure is 45 LBS and that is what it has, not 90 etc. However today I noticed a long run and I opened compartment and your could hear air rushing out so I cut off pump and no more sound and it is holding pressure. Do I have an adjustable pressure that I could set down to keep pump from continuing to run after reaching a level and then just letting air out???? Thanks Dan & Jo