Something I been meaning to mention but keep forgetting is
check your coil connections.Ignition coils have a distinct polarity, in terms of positive and negative circuit connections. I cannot count the numbers times I've traced the cause of ignition issues and poor performance to reversed connections on the coil.
Your coil should look like this:
The black plastic 'tower' in the top center is for the high tension lead (also called high voltage wire) between the coil and center of the distributor cap. The two metallic studs and nuts are the primary wire terminals.
One primary terminal is labelled plus (+) and the other is labelled minus (-), using black-on-black raised symbols molded onto the cap. These symbols can be difficult to see, due to dirt, grease, viewing angle, and amount of available light. The plus symbol is clearly visible next to the lower left primary terminal in the following picture. You can see the minus symbol, next to the upper right primary terminal, if you look carefully.
Reversing coil primary connections will
not affect the coil or ICM (or points if your engine's that old). It
WILL affect spark plug operation and efficiency, leading to significantly reduced engine performance.
On Dodge OEM ignition systems, the wire from one end of the ballast resistor
should be connected to the coil's positive (+) terminal. The coil's negative (-) terminal
should be connected to the appropriate terminal on the ICM.
Refer to previously posted or linked-to wiring diagrams for which is the appropriate ICM terminal. I did not try to describe which terminal because of the potential for confusion. (A picture/diagram is better in any case.) I also did not specify wire color because there in no industry-wide standard for color-coding wires. Manufacturers tend to have internal color-coding systems but even those can very between different models and from year to year. Furthermore, a replacement ICM pigtail may not follow the original color coding.
BTW, I specifically mention exactly where the coil-to-distributor lead goes because I ran across a case where someone had connected one spark plug wire to the center tower in the distributor cap and connected the coil lead to the empty outer tower. (This was a definite 'put the tools down and back slowly away from the vehicle' individual ... he wound up giving the car to me after he had totally and hopelessly messed it up.)
