560SEC 1989 tends to turn off but won't

[zcc]

On my 560SEC 1989 recently it tends to turn off but won't. I did the followings:

1. Checked the 8 spark plugs and all are good.
2. Changed the 8 spark plugs wires with original Buro ones.
3. Cleaned the rotor and its cap.
4. Changed the coil with original Bosch one.
5. Aligned the fuel distributor properly.
6. Checked the idle module and idle valve.

After all I still have the car on idle sometimes tends to self-stop the engine be it doesn't, any idea why? Thanks : ))..