Question: Periodic loss of air pressure

[tdieringer]

A couple of months ago the tire pressure monitoring system on my 2005 indicated that the air pressure in my front left tire was low (it was) so I aired it up. The following weekend went out for a drive and encountered the same problem. This happened a couple of more times several visits to my local tire shop each time couldn't determine what was causing this. No damage to tire or wheel.
My Chevy dealership couldn't determine the source of the air loss either, but "reset" the tire monitoring system and the problem went away for a couple of weeks.
This past Sunday I went out and the system indicated that my right rear tire was now showing 15 psi while the other tires were registering 30 psi.
Has anyone else encountered this problem? These are the original Goodyears with 10,800 easy miles?

 

[Tuna]

When your tire shop and dealer looked at the tire/wheel, did they break them down and look for problems on the inside of the tire?

Does the tire lose air just sitting in the garage?

 

[BigJimZ16]

There have been some porous aluminum rims in the past, maybe a defect???

 

[tdieringer]

When your tire shop and dealer looked at the tire/wheel, did they break them down and look for problems on the inside of the tire?

Does the tire lose air just sitting in the garage?

Yes, just sitting in the garage.

 

[LLC5]

Yes, just sitting in the garage.

You state that you are losing air in both the left front and right rear tires, was this comfirmed in both instances with an accurate tire pressure gauge?