I think you were hearing CSN repeater KVJC transmitting from near Globe when you lost K220FM.I was in North Phoenix this evening and decided to listen to this station driving home on the SR 51. I was able to receive it until I got on the Loop 202 at which point it started cutting in and out with a talk station. When I got off the Loop 202 at 40th St and started going North, this station came back.
The 91.9 frequency is going to be chaotic in the Valley soon. There is an LPFM run by the "School of Hip Hop" that will operate on 91.9 in Central Phoenix soon, and then KRPJ too. I feel bad for the Desert Soul Media people who will have to deal with that interference.