The car started running very badly sometimes: usually the warmer the air is, or the longer the car runs, it will be more likely to hesitate under load, sometimes severely. Sometimes, if I shut it off and re-start it, it'll run fine for awhile.

The check engine light blinked on, and eventually stayed on.

Could this be from a bad O2 sensor? The one on the car has two wires coming out of it. Went looking for one, and there is 1-wire, 2-wire, 3-wire "universal" ones, with some people talking about splicing the wires different ways... I'm not a real mechanic, so not gonna try all that, but at the same time, I really need to save some money, so sure would like to find a good universal one for cheaper ($150 would be a real strain on my budget)...

Then there's also some that say "driver's side" or "left side"... Is that just because it's on that side of the exhaust pipe, or is there more than one or something?????