Alright, so after some searching I still can't find out what this plug is for. It is a green plug that was just resting on the top of the motor. I read that it might plug into the cold start injector, but there is already something plugged in there. This green plug looks identical to what is already plugged in there too. Anybody know anything about this?

 

The split in that front breather hose has gone too far, you need to replace it ASAP!

I couldn't say for sure so I withdrew my original answer.
However I did find a couple pic's on this forum where they were working on an 86 22re and it was stated that connector goes to the Blue fuel pressure up VSV.

This looks awfully strange to me because I have a 91 22re and it has one blue VSV and one red/brown, both of them have the same color connectors hooked to them.





It looks like that Blue VSV is MIA in your picture. It could have stopped working and someone deleted it.
You might want to read this http://www.4crawler.com/4x4/CheapTri...ine_Pix/8.html


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Might be why it is not plugged into anything.

Cool red vacuum hose!!

 

Yeah it looks like the plug that goes to the VSV for the pressure regulator. There should be a VSV in the vacuum line between the manifold and the regulator. I've seen people remove the VSV and just run the vacuum line from the manifold straight to the regulator.