Idle Speed and Air Temp/Humidity Options

[StarBear]

As getting ready for the 2022 Northeast Gathering, I'm encountering a semi-recurring idle issue on my 1974 1.8L LJet FI. When outside air is cool and dry, idles just fine at 950-1000 rpm. When outside air is warm and humid, after warmup the idle falls off to barely running. I've just been adjusting the air flow screw (maybe 1.5-2 full turns) to open it. Of course, the reverse happens - if I preadjust the screw it idles near 1800 then settles down to 1100 after the engine gets totally warm (15 mins or so).
I presume (?) there SHOULD be some regulation, perhaps with the ECU or AFM, to monitor air temp and humidity and make adjustments automatically? I didn't have to manually do this adjustment in the past.
The AAR works and tests out fine. Just annoying to have to pull over after running a while and adjust the screw. (IMG:style_emoticons/default/dry.gif)
Your thoughts @Van @Van_B and @Wonkipop ?

[Van B]

What I previously described is my method to see if the throttle plate is seated properly when the throttle is closed. And is best done when the car is running so you can hear a change in engine speed vs detecting 1-2mm of travel with your mits.

Springs and levers and such can get dirty and gummed up which obviously make for stick points in the travel.

But I say get the car up to temp and idling steady and then try to push the arm “more closed” and see if idle drops, even a little. If it does, it means your throttle plate and bore have worn. That’s what’s wrong with mine and will require a rebuild.