Sudden, severe A/C related stalling & sputtering
 

So I took a 280 mile drive today which ended in some interesting occurrences.

It appears when ever the A/C is turned on or the turn signals are turned on, the tach goes absolutely apey and flies all over the places. Also at highway speed it seems to sputter a tiny bit, which I'm guessing may be a misfire.

After the trip, turning the a/c on can cause the car to rough idle and eventually stall. Same goes for turn signals. I couldn't pinpoint it to other electrical draws because when the radio is on, there isn't a similar issue.

I want to point out, its a new crate motor that has been working fine for 5k miles, with new plugs, plug wires, and fuel filter. But I have had some idle irregularity when the A/C was turned on and some rough start problems. Car is stock btw too.

Heres a link to my rough starts.

YouTube - 94' Miata Cold Start

Please help, I have no idea where to start.

p.s. i are is a mechanical noob. It seems the day I start thinking the car is running straight, something else goes (I literally was planning on installing the turbo & megasquirt next weekend)