So here it goes....
I've replaced a bunch of parts.
Cap, rotor, plugs, wires, and a new coil.
I replaced all the injector leads, and cleaned the contacts. Then tossed a new timing belt in for good measure.
Checked the CHTS by eye. It looks good.. lol

But this started happening randomly. One day it just started missing. I made it home, and shut the car off. Went back out a few hours later. Started it, and ran fine till warm.
Then it started missing again.
It's tossing code 21.
It definitely feels like it's an ignition issue, but I'd like some advice on pin pointing what it could actually be.
I also noticed my alternator is whining a bit..

CAS?
Ignition module?
The distributor itself?
Voltage regulator?
🤷‍♂️

Possibly Intake air leak or loose spark plug! Put a timing light on all the plug wires to find the miss....

I forgot I had asked.. lol
I worried it might have been the intake.
But it turned out to be a bad CAS. Some how it had shorted out in the past. A new one smartened it right up!
I also replaced my old ignition module, and upraded to the PRW-2 with a new hanshin style coil.
The old girl has never ran so good...

I have a 3rd Gen that's really close to the 2nd Gen design wise...I threw the entire ignition system in the trash and installed a Mallory ignition system with a huge oil filled coil...I owned a D21 Hardbody p'up for 20+ yrs and I had so much trouble with those solid state epoxy coils you can't give me one!

I thought about rewiring a standard coil into it..
Are you using your stock ICM?
What all did you change??

I 'm using the Oem ICM but I added in a Mallory 6A Ignition box and this oil filled coil...