timing belt easy to install? Oxygen sensor?

Had sensor checked at autozone, would that cause it to stall if it's been running faulty for a few months? I thought I might have a vaccum leak. Then I heard something like dragging brush under the car and it would lose power. Don't know if I should start it up that would damage valves if belt was bad?

If a timing belt goes, the car won't run at all. Sounds like you may have something else on your hands. I would have a mechanic look at it. It's possible that the valves could be damaged, but the metro is a non-interference engine, so it's not likely.