Chrysler Repair: Fuel injection issues: 02 3.3L T&C, engine controller, degree day

Question
Last summer we had the xmission replaced in our 2002 Chrysler T&C with the 3.3l v6 and upon getting the vehicle back we also noticed that it wasn't idling properly and had poor low-end power.  Took it back to dealer and they changed out 3 bad plugs.  Picked it up, didn't make it home.  Dealer replaced wires and tested the injectors and said they all appeared fine.  Again, didn't make it home from dealer.  They took it back and swapped the injectors/wires around.  Originally 2,3,5 were misfiring, but after the swap everything appeared fine for a few months until our first 95 degree day.  Same issues with bad idling and whatnot.  I checked the plugs and some were wet with fuel.  Now I was going to take care of it myself as I assumed this meant it was just bad wires or injectors but after I tested the computer I got codes for 1,2,5, as well as the system was too rich and the sensor heater circuit was malfunctioning.  So is my first step still to replace the injectors or do I have a major underlying issue here?

Answer
Hi Chris,
The individual cylinder misfiring can have many causes so I wouldn't assume it is the injectors. Please tell me all the specific 4-digit code numbers that are stored in the engine controller memory and then we can piece together an approach to try to resolve this.
Roland
PS Sorry for the delay but I just found your question in the pool to which Kevin had referred recently.