when at idle my car literally shakes all over the stick shift rocks back and forth basically feels like a 400hp muscle car, although its cool, i think its hurting performance and gas mileage.

Any ideas?

 

Engine mounts?

 

My Car Did That For While Until Finally My Crank Pulley Fell Off. Thats Why Mine Was Shaking But Thats Just Mine IDK How Yours Is>

 

I would lean to this too. Also, check your mounts and trans mounts as well.

 

Engine mounts are good, i checked those. Ive heard crank pulley have issues on these motors, i might wiggle that abit.. i dunno lol

 

Before we all take stabs in the dark, how about some more info?

When did this problem start? Right after the battery cable incident? (https://www.zdriver.com/forums/280zx-s130-forums-77/280zx-electrical-problem-any-help-32722/)

Does the car run fine except at idle?

What is the idle RPM?

Have you tried checking:
Timing?
Spark Plugs?
Wires?
AFM?
CHTS?
Vacuum leaks?

 

Boring..... maybe there are too many light bulbs on one side of the car and it's throwing the weight distribution off.

Timing.... pppffttt....

I do like the spark plug wires theory though. Kinda like my light bulb "stab in the dark" as you call it.... It's gotta throw the balance off if you've got all six on one side. Try moving three to the other side. You might need to tap new spark plug hole into the combustion chamber though.....

See "stabing in the dark" might just find us a solution!

 

LOL FRICFRAC!

this was before the battery incident, all hoses, wires, and plugs were changed. i did the vacuum tests and none changed idle, it idles at 750, umm i dunno what afm and chts its?? lol. timing isnt checked but i will have to some time.

 

LMAO i like your theory!