rims refuse to adhere to tire causing low tire pressure

Noticed the problem worse in the winter. I had new Cooper CS4 tires on the stock Alloy rims equipped on the SEL Package. I was constantly filling the tires with air. And one day my mother borrowed my car and before to even got on the merging ramp to the interstate the front passenger side tire was flat. So I met up with her, put the spare tire on and took it to the tire shop I got it from. And as it was still under warrant it was replaced free of charge. But the problem didn't end their. eventually I thought it was the tires themselves so I have Firestone tires installed and once again the same problem! After talking to a friend who works for Ford. He informed me that he has seem this problem alot. I myself was in rage at this point! I have never felt so ripped off in my life. He then told me I could purchase new rims, but that would not necessarily solve the problem. So I ended up spending $2,500.00 roughly and I have not had a problem since. That is the only problem I have had with my car so far. It was a pain. but to be honest my new rims look alot better on it.