3.6l always runs out at cold start, but then has..

...after 4-5 gas discharges its stable idle.

Hi,
I have only recently (3 days) a '91 3,6l and am therefore still quite inexperienced. I have the following problem since last night (no problem yesterday morning):
I'll start the engine, he'll be right back out. Second attempt, the same. Third attempt, as usual.
The fourth time I kept him alive with the accelerator. After four to five gas jets, everything was normal.

Since he didn't have that on the test drive, nor on the transfer day and the days now, I was a little surprised. I thought he might have swallowed himself for a moment last night. But no, this morning and this evening exactly the same problem.

What's the cause?

Can you help me?

Thank you
Kurt