I have the same exact issues and have been working with my dealer for 2 months to get it corrected, luckily it's still coverred. If it is an intercooler, it will not show in the standard Chysler collant system pressure check, thier collant dye checks or coolant exhaust gas checks.

The car will need a intercooler pressure test for leaks or you can pull the intake manifold and look for the stains. The plugs do not show discoloration unless you have a head gasket leak as the coolant is being too evenly distributed to the cylinders with a minor intercooler leak.

My O2 sensor also failed and the car was showing cylinder misfire codes, I think this is a common early onset of the coolant being burned, the O2 sensor failing will show on different cylinders at different times.

Are you using a dealer to get it fixed? If so I think we should get them both talking to save you some time and trouble.

I'll send you a PM with my number.