Gentlemen, only after filling up the car struggles to start. I don't have any codes, but it's quite obvious it's the so called purge valve, that doesn't close itself. Therefore the fuel fumes get pushed to the collector during tanking, then the car gets a mixture that is far to rich, then, as said, struggles to start. It's not a big thing, I can live with a workaround.

Therefore the question is: what is the exact procedure for venting the cylinders in a X350? Like the one to be used when the car is flooded with fuel? I assume you just press the gas pedal to the floor and turn on the ignition, but: do you have to have it depressed all the time? How many turns? Does it stop the fuel delivery only or the ignition spark as well? I didn't have an occasion to try, so is there anything else I should know?

yes put it to the floor before you turn the ignition on, and crank. when you take your foot off the floor it will spray fuel again, no need to shut off key and crank again. to test your theory, pinch off the hose to the intake from the purge valve and see if it stops

Thank you very much. Just to clarify, should I:
1. Floor the pedal,
2. Turn ignition on,
3. Start cranking, and after a second take my foot of the pedal?

Saying pinch, do you mean I should squeeze the hose to stop the fumes during tanking? Now why didn't I think of it myself. That's proof your gurus' experience is priceless, IQ is definitely not enough to reach such obvious conclusions Thank you again.

yes and yes

Just to share: I've just been at the gas station, and the idea worked - one second of cranking with pedal floored, and at the next crank engine started as it should. If I wouldn't do that, it would struggle for a couple of seconds at around 300 RPM and pick it up (usually) or die. Next time to be tried with a continuous crank.