I have a ****ty 2000 Dodge Neon that has been nothing but a pain in my *** since I got it. Today I was driving up a slight hill when the check engine light came on and flashed then stayed on. The car was jerking like it wanted to stall on me. When I got it back home I got the codes P0301, P1684 and P1685. The one for the invalid skim key I don't understand I have been using the same key since I got it so there should be no problem with that. I am sick to death of this car and if I could get rid of it I would have already. 1 complete engine change, 6 alternators, 1 alt tensioner, 2 fuel pumps, and various other repairs later I have put more into this thing than it's worth. I have tried to look into a lemon law but the damn car is too old or some ****. At my wits end and not sure what options I have left. Anyone have an Idea?

 

P301 = Cylinder #1 Misfire
P1684 = The memory has been cleared within the last 50 Ignition cycles
P1685 = Invalid SKIM key
Possible causes:
Incorrect VIN in PCM
Invalid SKIM KEY not present
No VIN programmed in PCM
PCM defective
SKIM trouble codes set

I had code 301 a while back.. Mostly needed a tuneup but I do need to replace the ignition coil because terminal #3 is severely corroded. And it did the exact thing you're explaining.. As for the alternator problem it seems like you might need someone to sift through your wiring harness and find shorts/opens.
Did you ever get the old alternators tested before replacing?