I got my 83 crossfire back in december. When i got the car the only electrical issue was that when you have the headlights turned on and turned the dimmer switch for the guage lights on the whole right half on the guages go nuts... They do the same if i use the right turn signal... The parking lights come on when i hit the brakes... It was cause for concern. But didnt hurt driveabilrity... Early this month i changed the upper and lower intake gasets, valve cover gaskets, starter, battery, battery cables, IAC valves, MAP sensor, new belts., MSD cap and rotor, new plugs and wires, both throttle bodies rebuilt and re balanced...
But just the other day she was running great. Went to work, when i left i let it warm up for a few mins. I live in iowa, crappy cold weather.. got about 2 miles dwn the road and the tranny started grabbing and dropping gears, my guages went nuts, radio was in and out, heater fan was up and down. Later that same night i lost all acc power but the car was still running til i stopped, could let it sit for awhile and it would fire rite up. But now it wont go 4 blocks without having total electrical failure, already had the alternator tested by Advance auto parts. Came back good to go. Can someone please help me figure this out?! This is our only vehicle right now in a family of 3... Thanks mike...

 

That many eletrical problems could be ground related. Your battery cables are new, but did you check or replace the body ground strap from the rear of the engine?

Temperature changes (either ambient or due to the engine heating up) can affect affect continuity on a connection that's iffy.

 

Curious if you worked on this, or found your problem?