3. The voltage is lower then 10.5V while cranking. Rather than trace all wires, clean grounds, etc. etc., my quick test was to jump off of my truck. It fired up and I had it idle for 30 minutes or so. Soooooo.....I figure I need to fix the "low voltage problem". There's no rush on my end, so that's a battle for another day.
easy to clean main grounds (forget that twin battery solution!)
clean the grounds, even if they look ok, undo, remove, clean, replace, protect.
The main ground is the negative battery cable bolted to the trunk floor. Remove, sand it clean, replace with some copper grease.
ECU grounds: there is a bundle of several black wires bolted to the rear of the cylinder head, passenger side, again remove, clean replace, protect.
The main copper earth braid wire under the car, transmission>chassis, passenger side: this is a later spider but basically the same thing: https://www.alfabb.com/bb/forums/129079-post2.html
then there is the main 'power' connection block (big red starter wires going to/from it) which is a small black block in the engine compartment, on driver's side inner fender. Check and clean all connections.
when all that is done recheck the crank voltage....you need about 11,0 volts.