That's interesting. I've read that one of the reasons that bipeds are more efficient runners than quadrupeds is because our breathing is decoupled from our stride. Quadrupeds' lungs are anchored within their chest cavity at the top and bottom, so as they stretch and contract their bodies, they are forced to inhale and exhale correspondingly with each stride. It sounds like you don't enjoy the same benefit as the rest of us bipeds.

That being said, when I do try to maintain a regular breathing pattern when running, I usually also do two-in, two-out. Feels pretty good to me.

Haha, I had no problem breathing out of sync with my stride but God did I sync my steps with pavement patterns :D.

Hm, I wonder if there is a term for this. I too like to try and keep in a pattern, and it never works out and often feels very unnatural when speeding up or slowing down a run.