My Trailblazer is now making a noise from the motor. Sometimes it will do it and sometimes it won't. It sounds like a something rubbing am I thinking the piston but the sound is slow any help will be appreciated

 

The TrailBlazers dont have a counter-balancer, and do normally move a lot. My buddy just bought a used 2000 TrailBlazer, and his sounded like a can full of nickles at first, but we found two very loose motor mounts. We tightened them down, and all the unwanted noises went away.