I'm a nuub.
I recently acquired an '81 RX, and the the shutter solenoid is plugged and the sensing tube from it to the coasting valve is deliberately plugged. The hose from the coasting valve to the air cleaner is also deliberately plugged. I reattached them, but it seems like the idle is a little lumpy since I did - like there is an occasional miss. Does anyone have any idea what the reason for this is?

 

When the shutter valve goes it causes some problems for the rear rotor. It's original intent is to close off the fuel/ air mixture to the rear rotor when decelerating and allowing air only into the rear rotor to avoid a strong vacuum from being created. Mostly, this is to aid with emissions. I disabled mine last year when it started to make a loud honking noise near idle. I would recommend closing it all back off again.

 

Thanks. For the advice. I shut it back off, and it idles almost perfectly, now...and the "whoosh" is gone.

I wish I could just remove the entire rat's nest. I am afraid I would never pass emissions, though.