I re-read the OP's resolution.UPDATE
....and basically told me that Chrysler claims carbon build up to consumer negligence and that's the way they can get out of warranty repairs....
This one statement from FCA is such a load of crap. If it is due to consumer negligence, then it should be suggested in the owners manual that it needs to be cleaned every so many miles. What is the negligence? Driving the vehicle? Does FCA expect people to buy their trucks and use them as lawn ornaments? Really dumb.