2009 Dodge Journey - Seemingly electrical problems, lots of codes, not sure what to check next

I've got a 2009 Dodge Journey with about 140k miles on it. It's been pretty reliable until the past 6 months. Things seem to be going south, and continue to head that direction.

I have gotten P1128/P1129 (always together) codes several times over the years, and the dealer has told me not to worry about them. They only happen when it's colder out (mid-winter, generally).

This year, since late summer, things have gotten worse. I've had P0300 and P0339 codes (misfires and crankshaft position sensor) going off. On occasion, I get all 4 (P0339, P0300, P1128, P1129) at once. The P03XX codes are ALWAYS associated with a bump in the road. I'm also noticing that when I hit a bump, small or large, I am often having the tach drop, the engine chug/stutter, and sometimes the check engine light comes on.

Last week I was traveling for work, and things were more interesting. I had the engine die on me twice. Once I was moving slowly (10mph), the other time at a stop. Both were horribly inconvenient times which almost led me into accidents.

I have done some research, and it's sounding like electrical problems to me. I was watching a graph of my O2 sensors once, and when my tach dropped, all 4 of the O2 sensors pegged their voltages and stayed there for about 5 seconds. I don't necessarily know what normal looks like, but this was definitely uncharacteristic of the rest of the graph that I was watching.

I've taken this to a dealer, and they've got no ideas. They want me to bring it back in, but I've asked them to give me some sort of idea of what I can do to try and provide more info to them. I want them to have an idea of what they're looking for before I bring it in (I can't go without a car for long).

Anyone have thoughts on this one? I'm starting to regret not trading this in for my wife's new car last fall and keeping my Saturn. But, now I'm stuck with it.

Thank you in advance.