96 TALON ESI Idleing problem please help

Ok guys i could still use some advice please!!!! I ran the car for awhile and finally the check engine light came on so i had it scanned it said the car is running to rich. So what can cause this? What can i try changing. The car runs great while your going but when you stop the idleing jumps up and down sometimes almost stalling. Again 96 talon 2.0L DOHC non turbo only 85k on it.
THANKS ALOT

Do you have any mods on the car? Its probably just a sensor or something, maybe an o2 sensor.

no mods to the car at all. Thats what i am thinking just a sensor, but wouldn't the computer show a code if a sensor is bad, all that comes up is the oxygen sensor saying the car is running to lean.

My 94 Eclipse Gs did the same thing.One day I am just driving down the
road and next thing I know the Check Engine light cuts on.The next morning I go to get into my car to go to work and it wont hardly crank,starts flooding and the idle was horrible.It turned out to be my 02 sensor and you could also check your Tps that may have something to do with it as well.Good Luck!