So my z is idling to high and there is a hole where it looks like a screw should be in that when plugged up makes my car idle normally. I can't for the life of me find what goes hooked up to it or if I should plug it up. Can you guys help me out?

Looks about the size of the one that supplies the heater control vacuum bottle.  Just plug it up until you find the vacuum operated thing that doesn't work right.  It's nowhere near big enough for something like the brake booster,

Looks like a perfect spot for a distributor vacuum advance hose.

On 9/14/2020 at 11:54 PM, LeonV said:

Looks like a perfect spot for a distributor vacuum advance hose.

That's what I was thinking