Thank you for your reply.
I did the IMU calibration several times without success.
I bought new propellers a few weeks ago via Amazon. I thought the supplier was DJI and used them for a few flights without any problems, then suddenly I had this jumpy drone.
After reading a ton of threads I decided to install a set of used original propellers. The problem is solved.
Old sparky is running smooth again. It was the 3rd party propellers after all. Now I sit with 12 new unusable props in my bag. Not the biggest problem in the world though.