Did a search, didn't find anything, so - recently we received a safety notification from Ford advising us to check the valve stems on our '07 vehicles. Seems they're developing cracks, allowing the air to leak out. Some info.
Originally Posted By: HTSS_TR
The infamous Chinese valve stems !!!
If they can't get us with lead in kids' toys, they'll do it with melamine or defective drywall; whoever is left will get wiped out by faulty valve stems...
The commonly available valve cores for Schrader valves are also of bad quality. Ever since I replaced the valve cores on all my car and bike tires with a good brand, I have had to add more air much less often.