Cant zoom in on amplitudes

Either I cant figure it out (most likely), or you cant zoom on the Y axis. I was trying to determine the frequency of the audible vibration my car was producing. The peak amplitudes just blend right in with the noise when its zoomed all the way out.
Also, sometimes the actual graph disappears. It will still show the frequency of the peaks, but the rest of the screen is black.

Jasonindahouse about Audio Spectrum Analyzer, v1.4.2