I have a 2011 Jeep Liberty Sport 4WD, 3.7l OEM status. I have had various ODB codes over the last few months, starting with P0133 and P0420. I replaced both upstream O2 sensors and also the spark plugs. It ran well for a few weeks and now is much worse with rough idling and more codes. The last set of codes included: P0133, P0153, P0172, P0300, and P0304. It is in good shape and has no leaks and no noises. Could the coils be bad and if so, can they be tested some way? I assume misfiring could lead to a rich gas situation but I don't understand the problem with "slow responses" from the O2 sensors. Please give me some ideas from experience or knowledge. Thank you.