So since I've finished my gas tank adventure and the trans. project is on hold until parts arrive, I'm removing the old smog/air injection pump junk. I took off the big pipe system and now I just have the injectors.

Do the injectors thread in? They have a nut at the top for a socket but the haynes manual doesnt show threads in the diagram.

They're also full of dirt and crap , never a good sign

They thread in. Best thing to do is to take them off and plug the holes using 10mm VW valve adjuster screws using high temp lock tite to keep them from moving. I did this on my old 2.0 and drove it a long time with no problems.

Yeah, I carefully kept turning one until it threaded out, so I already had that answered. Here's some pics for the enlightenment of the masses...

The main injector piping:

the first injector out:
Click to view attachment

and inside, the whole system is full of :

I left the injector pipes in and capped them with a 3/8" NPT pipe cap.

Yeh I know Krusty, the threads are not the same but it worked.