When the car is on idol or if its running the engine seems to be missing. on 2009 Kia Rio

It doesn't excellerate like it use to and the engine light stays on.

4 answers
scan test for codes and go from there
agree scan codes and post you most likely have misfire data in ECM
Coil on plug misfire, as stated scan test needed to determine which cylinder is the problem.
Check your coil packs. I have a 2007 kia. No problems until this summer. I have replaced 4 coil packs in the past few months. First signs are check engine light comes on and the car begins to start missing. Excerlation decreases...
not a happy kia owner at present!