Re: Miss fire
The after cat O2 sensors are not used for the fuel trimming, only for measuring the efficiency of the cats. If they donīt work (well), the engine should perform normally.
Mopar is not the manufacturer of the sensors, but they use Denso on the WJ. I bought new Denso sensors for around USD 25 each via internet. Other brand sensors (like Bosch) heat up more slowly and the PCM interprets this as a failure.
Hard starting can be caused by various reasons. Is it allways hard to start, cold and hot? If you prime the fuel system three times before starting, does that make any difference?
If not, have a look at the inlet temp sensor value, to see if its not far of.