Low Idling and wants to almost stall when you give it gas?

[spray2020]

I originally had taken my car apart- ca18det manual (1990 s13 silvia jdm import) - and disassembled the air box/ MAF sensor (unplugged it), charge pipes(all stock), intercooler (stock sidemount), drained the coolant, battery and fuse box (unplugged and ungrounded)-

I've never owned a s13 before, so I wanted to get some knowledge of how some minor things go together.

Then I put everything back together and when I tried starting it for the first time- I didn't realize that I had one of the ignition coil connectors disconnected- It was obvious once it started, so I then went
and connected it- and started it for the second time and it was idling pretty low-around 700-800 rpms

The car feels very sluggish- when you give it gas and let off the rpm's drop almost to nothing, almost stalling and then go back to the 700rpm range- but the needle wavers a bit. The power window switches dont work any more, but when I press them the rpms go lower, as well as the lights.

I dont even think I could even drive it-

Could it be a blown fuse? MAF sensor? I dont see how that sensor could go bad by just unplugging it? Vacuum leak?

The car was running rich when I bought it, but didn't have this idle problem, so I am guessing it has to do with something I did.

One concern is when I ungrounded the fuse box and unplugged it- I didnt remember correctly how the grounds went back together- one for the negative battery terminal and one for the fuse box wiring-
But I grounded them to bolts- and made sure the connections were clean so I don't think that should be the problem.

Any Ideas?