[ischmitz]

Have you checked what's preventing the lever from closing and hitting the idle switch? A properly adjusted stop allows the lever to hit the stop while at the same time depressing the idle micro switch. The idle switch is needed to get stable idle. Yours looks like something is preventing the throttle plate from shutting all the way. Maybe there is some gunk inside the throttle body obstructing the throttle plate. Or the return spring it not strong enough or the shaft needs lubrication. Or something else is obstructing the throttle lever. Hard to tell from your photo. I would remove the throttle body and examine it. Then once it moves freely put it back, and only connect the throttle cable and go from there.

Assuming no one has tampered with the adjustment I'd leave it alone. If you have to adjust it from scratch first you need to adjust the stop position. This has to be done with the ICV centered (by inserting a paper clip into 3-pin diagnostics plug). Think of the ICV as a variable bypass to the throttle body controlled by the DME. You want the engine to almost meet the idle condition with the ICV centered so it later has enough range to regulate idle. This is done with the engine at operating temperature. Once the idle switch is pressed the DME goes into a closed-loop mode. It regulates the ICV to maintain the 800 RPM or 880 RPM (later models).

Next, the micro switch might have to be adjusted relative to the stop so it gets depressed but not loaded up by the throttle lever stop. It can't be misused as mechanical limit.

Ingo