Hi Bob,
I’m Don, I’ve got an ‘05 HR Nav, too. I had an issue with my airbags letting air out of the right side when parked for more than a week. I believe there is a valve that separates the 2 sides and my mechanic changed it out and I’ve not had the problem since. You might have the same problem. As far as the gages, the air IS the left one, the right one is your turbo boost pressure. Keep an eye on the right one while climbing grades. Don’t let it peg, ask me how I know…I blew the turbo boot cover off mine in N. Idaho and had to get towed. Don’t do that either…I’ve had mine almost 4 years and have had lots of issues, but lots of fun, too. If you want send me a text 925-784-5165. I’m in NorCal.