Rough Idle disconnected part near back left

When i cold start the engine I'm getting a rough idle where it sounds like a tractor. As soon as I get on the gas it goes away and runs smooth with normal sounds. Inspecting the engine the sound is coming from the back left and I found this mating plate was decoupled. What is the name for this part and is this the likely cause of the rough idle?

 

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Welcome from Wisconsin!

 

Ended up grabbing some 5mm machine thread bolts from Home Depot and was able to get 3/4 of them in with an allen wrench. The upper one closest to the engine didn't have much finger room without disconnecting all the hoses.

I found out the part is called the "Reed valve assembly", part #Toyota 17350-65010

The rough idle seems to be cured for now.

Also found this thread where someone else had a similiar issue:
https://www.yotatech.com/forums/f116/pair-reed-valve-95842/

 

Yotatech is the best source (archive?) for '86-'95 generation stuff. This site is largely 5th gen. content discussing drain plug gaskets and air filter change intervals.

 

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