Audi jerks in cold condition

HI!

My Audi A6 4.2 liter V8 BJ 1999 has a problem.

In the spring, the car began to jerk constantly, with power loss, the right bank of the Lamda probe was replaced problem fixed.

Then after a few weeks, the car only jerks in the cold start the speed was also lower, after about 30 sec everything was normal again. In a warm state, no problem starts.

The car was in the Audi contract workshop, no fault in the diagose, the vacuum hose was replaced, problem seemed to be fixed.

Approximately. 3 days later, when the cold starts, it's back to scratch, but now it's only 15sec, then everything's back to normal. When I start with a switched-on climate, it's even more powerful.

What can this be? Ask for help.