Hello.
I have a weird problem with the idle of my car, a Mercedes 560SEL W126 M117 engine.
The idle must be a 650 rpm (+/-50) in P or N, and 550 rpm (+/-50) in D o R.

Now is about 1000 rpm.
I have 3 used idle control modules, with any of them the idle is the same.
I have 3 used idle control valves, and here is the problem.
I cleaned the 3 ICV soaked it for a few days in carb cleaner. I tried one of them, and the idle go to 650 rpm PERFECT!! But once the car is warm, the idle went again to 1000 rpm. So I tried another ICV with the engine warm, and the idle was at 650 rpm, but after drive 5 minutes, the idle again at 1000 rpm. Tried the last ICV and the same result.

Before I've changed the 4 pole temperature sender, but the older one was in resistance specs.
I check the miliamperes at the ICV idling= around 1000 Ma.
I check the Volts at the ICV idling= around 4,25 V.
I check the resistance at the ICV disconected= 5 Ohmns.

The idle switch is new and rechecked= Ok
There's no vacuum leaks, I changed all intake manifold gaskets, rubbers and vacuum lines and elbows.
The CO is at 1,5%, my car is NON KAT, so don´t have O2 sensor.

Any advice will be wellcome