1987 TBI K5 No spark

[edflores]

I Bought a 87 k5 350 tbi. Was running at a very high idle ( 2200-2700rpm). Previous owner put on a rebuilt TB. Checked everywhere for vacuum leaks. Found one at the TB base.Still high Idle. Performed TPS relearn. Idle dropped significantly but still a bit high.
Test drive and it dies as soon as you put it in gear. Would sometimes struggle even if you kept it alive, sometime ran like a beast.

I decide to do a tune up. I was advised to do a new distributor.
Replaced distributor, Coil, plugs and wires.
No Spark.
I have replaced ignition modules. Nada
Another new coil. Nothing.
Whole distributor again. Nothing.
I did the test on GM manual and I keep getting bad coil or module.

Injectors are firing while cranking so pickup/ecm seems good.

Only other thing that caught my eye was my dash volt gauge reads low most of the time. like 8 volts. Even if It gets to 12, it drops down very low while cranking.
I still have 12v at the coil though

Any thoughts or ideas?