Losing Air Pressure 3 out of 4

[SS&Sierra_84]

I've had my SS since Jan/Feb and I've been working diligently to get her into Day 1 shape or as close to it as possible. The factory wheels 3 out of 4 I've had to strip the tire off and grind down the Calcium build ups. The air had been slowly seeping out. I also had to replace a valve stem. Its not a major issue but I think I am going to go ahead and do the 4th and final wheel as a preventative measure. The previous owner of this truck kept the truck in good shape but she didn't bother to put forth the effort into the little things. Its been a pain in the @ss. I also found a type of paint that is for the factory wheels & supposed to guarantee no cracks/rust/or build up. I am going to clean up the factory wheels and touch them up and use them as winter wheels (mind you when I move, the truck is going to kept in the garage in the winter months), Once I finish up the other projects I am working on with the Sss I am going to buy new rims anyway. Wondering if anybody out there has had this issue...