Check the engine and ignition harnesses - if they are original biodegradable ones they are most probably bad on an 83 and will need to be replaced. They can be had cheap from Dave Barton (do a Google) and are not hard to replace especially if you are going to pull the intake manifold to clean the flame box.

Not knowing the maintenance history here are a few things to check:

Timing belt and tensioner
02 sensor
coolant and thermostat
both fuel pump relays connected to main harness under glove box area.
Hall pickup sensor under white cap/rotor - Chrysler ignition.
Tank pump, hose and filter
main pump and filter
FPR and injectors for spray pattern and for gasketleaks
Surging idle - CIS motor(IAC), vacuum leaks and throttle body cleaning.
OD should engage over 45mph in 4th. Older cars may not engage until around 55 -60 mph. Before you do anything radical, check the switch in the shifter, wiring which can be broken, and OD solenoid.