Just picked up what I hope turns out to be a steal of a car. Not real familiar with Saturn, but a friend needed to offload one and I snatched it up cheap. Anyways, it has a rough deep sound & some vibration at an idle and at low speed, gets better as you speed up but it doesn't seem to be gear-dependent. It's kicking between gears alright, but I took it up a steep hill with CC on and it started lurching pretty bad. Threw it from Economy to Power on the selector and it seems to be better. Idles at 800rpm or so. I'm hoping (?) it's a fuel filter or bad spark plug... feels like it's choking. Any other ideas?