@ Jeda 13 - I had the same problem with two rims. I just put new tires on today. The installer replaces the rubber seals inside the rim at the TPMS valve stem. One for sure was installed "off center" and was not sealing well. The other looks like it may have a small abrasion or cut in it causing it to leak.

I am not able to post a picture of the seals but it's pretty obvious that the seals were installed wrong and was off center or cut causing the slow leaks. I added air for 3.5 years. Hopefully, I won't have to do that anymore.

 

And "OCCUPY YOUR STREET". THE EVIL CORPORATIONS ARE AS BAD AS THE EVIL GOVERNMENT!!!!! more dancing fruits & vegetables