System too rich??

2001 Nissan Sentra GXE 1.8L 105000k miles.
Here is the problem that has occured suddenly and became worse. The engine shakes badly while stopped at a light or in park. The car will accelerate poorly up to about 2700rpm and then it catches up and starts to accelerate normally up to about 3500rpm and then it starts accelerating slow again. It feels like the fuel filter is clogged and the car is not getting enough fuel. Now the SES light came on. Took it to autozone. I cant remember the code # but it said that system or mixture is too rich (this code was listed twice).
Any ideas on what is wrong is greatly appreciated.

idk about the whole shaking thing, but the auto sentras tend to try and accell in overdrive till you hit about 2k if you were sitting at a light or somethin. best thing to do is to not floor it when tryin to move, otherwise it may do the whole struggle thing sometimes. did you change your oil, oil filter? or the air filter? at 100k miles, you gotta change the spark plugs as well, since nissan used platinum NGKs. those are suppost to alst for '100k miles'. try that and see what happens. your problem should be eliminated.

shaking = misfiring. get a tune up.
cap/rotor/plugs/wires/air filter/fuel filter