I have this problem for a long time now. And it is becoming worse.
Between the 1000 and 2000 rpm is the motor not running well. When I steady the throtte handle somewhere between this range, the engine falters.
I very rare occasions, the idle drop off to 800 tpm, while waiting somewhere.
Sometimes when I start the engine, de machine is very rough idling. It is possible to drive, and above the 2500rpm its no longer noticeable.
But the best solution is, to kill the engine and wait for a while. And the start again. Mostly the problem is gone.
The Throttle positon sensor is replaced 2 years ago, and there is 15000km driven. So I don't think that's the problem.
I removed the throttlebodies, and clean them, also clean de idle actuators.
I also mounted new oxygen sensors.
The problem is still there.
I noticed, that when I perform a calibration of de idle actuators with the GS-911, the problem is gone for a while. But it don't last long, the last time it did this the problem was already there the next day.
So I think there is not much left, except the idle actuators.
What do you think about it?