I think you are right. I took the side panel off when it started doing it and watched the mechanism with the balancer. It didn't seem to be doing anything abnormal, the saw would just go to full speed at second long pulses. The horse-like sound was the billows I believe at the top just putting out more air. When I put it at full speed it sounds like that. I had it in a power strip but I'm not sure if problems with that could make the saw speed up unless the saw has a bad resistor somewhere. It only started doing it at after about 15 minutes of running. I may just have to return it. I'm thinking of buying a new one and returning it the same day with the old one in the box, just to avoid any bull with the staff there.
If I return it and look for a new one, what would be a decent reliable saw for under $150? Is ryobi typically a problem brand?