I'm up in Grand Blanc and was kinda having the same problems as you. I could get all the Flint stations but channel 12 kept messing up over the past month. I had a DIY 4-Bay McClapp antenna in my attic made out of wood. I decided to build another one out of PVC, paint it black and mount it on the roof. I now pick up sold signals from all Flint stations, channel 6 out of Lansing, plus channels 4, 7, 20, 56 & 62 out of Detroit. My goal now is to try to pick up WJBK 2 which is real channel Hi-VHF 7.
Best antenna for under $10. Here is McClapps website:
http://m4antenna.eastmasonvilleweather.com/index.html