Promlem with Motion Zone & Sensitivity

Can someone please help with problems I'm having with Motion Zones & Sensitivity?I have a new Stick Up Cam Powered, and if I set the Sensitivity to Max, I get every passing car even my neighbors opening and closing the garage doors. If I set to to 75%, I get nothing, not even me pulling into my garage or pulling out.As you can see from my zone area, I don't have my neighbors or street in the zone, but it picks it up. My Signal Strenth is between 45 and 49. It varies throughout the day.Thank you.