Electrical charging problems

Pretty typical of the mopar alternators. They tend to not have sufficient output at idle. Check voltage at alt charge stud at idle.

A different alternator would likely help with electrical requirements at idle. I use the Denso's off a toyota in a lot of cases. Takes a bit of work on brackets/spacers.

300 rpm drop in gear is a big change. I know we have smog stuff to deal with sometimes. The tune up is a bit off with that much drop or there may be a vacuum leak somewhere.