How to solve BMW E60 520D 2007 Idle problems

I have following problem.

BMW E60 520D M47N2 Engine which has rough Idle.

Also when I start the car from cold, it works fine, but when it starts to warmup, especially when the gearbox lever is on P or D, or i start AC, or i start seat heating, the Rpm needle goes up and down , and the engine sounds like it is misfiring.

I have changed, Glow plugs, Glow Plug relay, Cleaned air intake, Swirl flaps are all ok, cleaned Air Mass Meter, changed Vortex Engine breather. The problem is still the same.

I did a full diagnosis with ICOM ISTA-D ISTA-P and no errors were found, and parameter checks are ok. Smooth running measure is ok, max +0.3 , min -0,2 on all injectors.

Then, a member in the forum advised me to do these work: check it I can force ECU to drop some DTCS in ECU, by unplugging MAF or EGR while engine is running as DTC table might be removed in the past, that’s why I might looking forever. He had few cars like that, someone disabled DTC in the car and diagnosis was more complex now he learnt the lesson,

Then, I learn the lesson from him, and tried to do these:

-try to unplug vital sensors for engine to double check if errors are dropped.

-inspect throttle body module, clean it

- have look on egr valve as it might be issue

- try to unplug egr and see if there is any difference

-check for bad ground some where in the harness, check all ground locations

- PLUGGED UP/CLOGGED up catalytic converter/muffler. Pre-existing condition was car running rich, over long time caused too much back pressure in the exhaust.

Finally, problem was solved by cleaning throttle body module.