What causes an engine on a 1998 Dodge Stratus to misfire while it's running?

I have a1998 Dodge Stratus with a check engine light. I don't quite know what the trouble code is because I haven't gotten it check out yet. The car is okay in park but when i put it in drive or reverse the engine starts running rough and misfiring and the steering wheel shakes violently. Is this one of the symptoms of a bad O2 sensor or Spark Plug Problems?|||it could be a bad 0-2 sensor or a bad set of plugs in it will even cause that to happen,when the plugs get so many miles on them the gap gets to far apart and causes a miss-fire in it under a load,have the computer scanned on it and id change the plugs in it also,any time you get a miss-fire code the plugs is the first thing you check,90 % of the time thats the main cause of one miss-firing,good luck with it.|||It could be anything from low idle speed, vacuum leak, bad plug wires, bad plugs, dirty fuel injectors, weak fuel pump, dirty fuel filter, bad ignition coil...blah blah blah. In other words, you won't be able to guess. You need a mechanic to check it out and fix the exact problem, Don't let them "guess" and start changing parts. Ask them directly when they suggest a repair, "This will fix this problem....right?" If the answer is not yes, don't do that work.