Service Engine Soon light

Put some Sea Foam in with your next gas fill up..helped my 03 Stratus (147,000) runs great

sounds like you have moisture in the gas tank. there's plenty on the market that will take moisture out of gas tanks. Home Depot, Menards, etc.

Kdog

Could be a number of things. You need to have the codes downloaded. Take it to your local auto parts store (Autozone or Checkers) and have them download it for free

When you replace the plugs you should also replace the wires. If you don't have a check engine light then you wont have a bad cam sensor. Stick to fuel and spark issues.

check for vaccum leak or check throttle body and clean

it's not likely a bad o2 sensor would cause it to run rough, but the catylitic converter, which is what the o2 sensor reads the flow of, would cause the car to idle and run rough.If you take it to an auto parts store to have a diagnostic test ran on it( most major parts stores will do this for free), thecodes it gets would help pin point it alot better.

If the engine seems to run fine over 1450 RPM maybe there is a vacuum hose leaking or EGR valve is slightly stuck open. Any help from the OBD II trouble codes? Or is there simply no MIL and no stored information in the OBD II computer read at the local parts store through the connector by the drivers knee?

What engine? You need to have it scanned for codes. Autozone will do this for free

check the fuel filter and when was the last time you had a tranny service done and a tune up also check the drivebelt

Maybe your service engine soon light bulb is out. Maybe hook the code reader up to it and make sure its not showing anything.

Let me know if you need some more help.