battery down ..?? had the key on and off for a loooong time.

11.2V is below completely discharged.

Something not right with your battery. Put a charger on it, charge it at least overnight and then take it to be tested with a load tester.

I suspect your battery is flaky.

You may have what is called a hi joint in the electrical world which means you have a high resistance connection that is going wide open when hot, now you already know it is in the ignition circuit so that limits the possibly of the problem part
You've already done a bunch of trouble shooting so now is the time to focus and fix it, the intermittent problems are always the hardest to catch and fix when they go open and cool down and remake the connection
Now get to work and fix it
You can do this
Make sure you have a good quality VOM and go step by step looking for the voltage drop between components and connections Start at the battery posts and go into the circuits to the ignition parts on the engine one step at a time
Do this test with the motor not running and write down the readings at each connection ands then do it again with the motor running fast enough to make the alternator charge at or above 12,5 volts Keep at it until you find that dirty little connection
How old is your ignition switch and lock?
Good luck, please let Ius know your results and findings

12.5V is still well below the proper charge rate.

Battery Basics

The charge rate is determine by the voltage regulator type and which year Mopar car your working on, the early, pre 1971, cars with the point type voltage regulators would discharge at night with the lights on idling below 1000 RPM so the car would run on the battery voltage
In todays world of dual field higher output alternators and solid state regulators that isn't a problem now
I've worked on Mopars cars that were charging under 13.5 volts at or slower than 1500 RPM
BTW, what voltage due you consider the "normal charge rate"?

Read the link.

The link says nothing about normal the charging rate of a vehicle.

I happen to have a factory service manual on my desk for a 1978 Dodge full size van. This would be an electronic voltage regulator system, but should be representative of the older charging system "normal" charging system voltages.
From the book quote:

Test: Start and operate engine at 1250 rpm with all lights and accessories turned off. Check voltmeter. The regulator is working properly if the voltage readings are in accordance with the following chart.

Ambient Temperature
near the voltage
regulator: ------------ Voltage range:
-20 degrees F ------ 14.9 to 15.9
80 degrees F ------- 13.9 to 14.6
140 degrees F ------ 13.3 to 13.9
above 140 F ------- Less than 13.6
It is normal for the car ammeter to show an immediate charge and then gradually return to normal position. The duration the ammeter hand remains to the right will be dependent on the length of the cranking time.

End of book quote.
If the operating voltage is below normal, the entire electrical system will not operate correctly. I believe the OP needs to find out why the charging system is not operating in the "normal" voltage range. Gene

I worked for three different telephone companies for 33 Yrs, we used lead acid battery to operate all of our office, the switching equipment that did all the work, was fed directly off of the several different battery strings in each office. We used A.C. rectifier to charge the batteries and used the batteries to act as noise filters from the local commercial A.C. network as well as run the offices 24/7 365.
I took some training in Palm Springs, CA in the summer of 1965, the training room we used was in the basement of the then new Palm Springs east Central office, it had batteries built and used in the main office before automatic switching equipment was invented and used that ATT had installed in 1905 in the original and only telephone office in Palm Springs back when telephone operators handled all calls
Each of those cells where around 18 inches to 24 inches square and around 2.5 to 3.0 feet tall incased in either clear plastic containers or glass
All of the lead acid batteries are two volts and the national telephone standard operating voltages in the central offices varies from 48 VDC to 52 VDC, depending on the company and area of the country and in the World
Every string was supposed to have a monthly inspection and preventive maintenance(cleaning and adding water) performed on them to prevent them from going bad, most offices had that done by one employee. I saw one remote office that had been neglected by the tech , he would sign off the P.M. work that he didn't do, which ended up getting him fired

Reread the entire link. It talks about the battery not the vehicle because it's what the battery needs and not the vehicle that matters.

If your charging system voltage is below the fully charged battery voltage spec you will never fully charge the battery and even then it needs to be well above the fully charged spec to properly do the job.

wow

Might be worth looking into this......
In 1981 I had a 1969 Charger with a 383.

At night the lights were always dim, turn signals would blink slow, and I always had a faint burning smell in the car.
I really didn’t understand the charging system that well back then, but even at like 2500rpm, with the lights going the voltage across the battery wasn’t even 12.5 volts.

I brought the car to a shop that specialized in auto electrical.

The problem was the ammeter had become a resistor...... and the more current you tried flowing through it, the more resistance it had.
They just piggy-backed the two wires onto one terminal, bypassing the gauge....... no more charging problem....... and no more burning smell.

I haven't seen anyone ask yet, is your pickup set to .008? My dart did the same thing yours I'd doing when I got it. I put three different modules in it and it would only run with the original but would die randomly. The gap between the pickup and the reluctor has to be exact.