Welcome to the forum
Note on the grounds - make sure that after rework
the original points that had grounds still do.
They provide not just grounds but also protection
from electrical interference to sensors.
Truck running well with timing wire unplugged
but not with it connected suggest IC mod or pick-up coil problem.
Specifically, with timing wire connected, ECM is looking for pulses
from ICmod/coil to control things, without it connected,
it just runs off base programming.
Ohm the p/o coil and be sure it's not shorted to ground.
Careful with the tach lead, even a momentary short
to ground can damage IC mod.
Hope that helps, let us know what happens.