70 Challenger column automatic sometimes will not start or run in park or reverse. Today It started in Park, then just died. Lights stayed on and it had electrical power. I got it started again then died while in reverse!

Where do I start?

Start with the neutral safety switch!
loose wires, linkage etc...

Thanks I will check that out!

If the car would crank and start with the key turned then shut off when you release the key, check the balast resistor.

It shouldn't start in reverse. If it does then your shift linkage is out of adjustment. It should only start in Park and Neutral.

OP – your thread title and your 1st post conflict a little, and for an electrical problem like this it’s easy to get the rest of us sidetracked if the specifics aren’t spot-on accurate.

LS-300 is correct on the ballast resistor clue, but I’d suspect the ignition switch also.

Neutral safety switch should only interact when cranking the starter motor, not at other times. If car will not start in park but will start in neutral then NS circuitry is to blame.

Ok it starts in Park sometimes. One time it just shut off while in park. Another time it did it in reverse. Everything is fine in drive.

Thanks again I appreciate the input!

If it only starts in PARK some of the time, it's probably a linkage problem. My Challenger did that and the linkage was all worn where it goes through the floor and pivots in the bushing. Sometimes it wouldn't go fully into PARK and then wouldn't start unless you put it in neutral.

I don't know what to tell you about the stalling issue.