Lately I've noticed that my car will occasionally (not all the time) do this sputtering/cutting out thing when idling. But if I turn my parking lights on, it completely goes away. Weird.
Now, I've got about 32 extra grounds on my car's chassis but this is obviously some sort of electrical problem.......

 

My guess is you need to adjust your idle air with no electrical load...

reason it clears up when the lights are on...the electrical load center tells the ISC to bump up the air bypassing the throttle plates and increase idle (ever so slightly) to make up for the electrical load increase.

Maybe look at your idle fuel mixture as well...seems a little rich if its sputtering. Maybe more air around the throttle plates will make up the difference, I don't know.


(you went a little overboard with the GND wires, eh? I have 2 on my engine (both stock locations) and 1 added on the chassis for my battery relocation.)

 

Well.....maybe 32 is an exaggeration...
I did add another ground off the battery, another off the UIM, and one more off the block by the starter. Doing that completely cured my 3000 rpm hesitation issue. This was done 4 or 5 years ago, by the way.

Now....I have NO idea how to adjust anything. And the sputtering is odd, first in that it only occasionally does it, and second in that it almost seems like the ignition is being cut more than a rich fuel problem. I mean the idle will be a perfect "hmmmmmmmmm" and then go "buh duh duh duh hmmmmmmmmmmmmmm buh duh duh duh hmmmmmmmmm" and so on and when it does the "buh duh duh duh" part the idle drops about 400 revs or so.

 

I have the same exact problem, in my auto, with alot of electronics as well. I have posted and searched and all I ever got was to adjust the TPS. Never got around to it though.