Sharan: Starting problems & engine stalls.

Hello everyone, I'm new here and I'm having a problem with my Sharan. It's a 1.9 TDI, AUY engine, with 283,000 km on the clock. Unfortunately, it's been almost impossible to start since yesterday morning, it's smoking heavily and misfiring. I read the error memory (VCDS), but no errors were stored .
"The preheating system was completely checked and is working correctly. After letting it run for a while and it started up, and I took it for a test drive, it suddenly stalled when I disengaged the clutch and wouldn't start again. After some time and several attempts, it started up again. There are still no error codes stored."
Fuel filter replaced, no change.
Can someone tell me if this issue is a known problem?

Thank you very much.

Is he/she/it performing at their best?

Does the AGR close properly? To test it, try putting a piece of metal inside.

Er läuft auf allen Zylindern. Habe das AGR heute früh dicht gemacht. Uunchanged.
"When it starts cold, it runs roughly and smokes excessively. When I'm driving and the engine is under load, it stalls when I release the clutch and then won't restart. If I drive carefully, avoiding the load, and use a little throttle, it continues to run and even idles. I've already been observing the parameters in VCDS, but I don't see any error codes."
While driving, I feel like there's a slight lack of power, but then I was on the highway, and there was no jerking or hesitation; it accelerates reasonably well until the next gear change.
I've been a mechanic myself for 28 years, but I'm at the end of my rope .

[Translating...]

Autoscan?

Air in the fuel system?
Crankshaft bolt tight?

Greetings.
Guste.