BMW 530 i 2005 jerking
 

I have the following problem: From time to time (short jerks) when accelerating from 1500 -2000 rpm. Only with a warm engine.
Both in the D and on manually (I thought at first that the automatic transmission hesitated in D)
I once had a broken coil (jerking at high rpm and a message misfire)
Up to now I have seen no error message. Also via the OBD can find no message.
I already replaced the camshaft sensors, no change.
The MAF already replaced without result.
I've checked several readings:

Short term trim, bank 1: ranges from +6 to -10, -10 when accelerating, bank 2 idem.
Long term trim, banking one: always in the minus range of - 6 to -3.5, bank two comparable.
Apparently the mixture without correction isw to rich (excessive fuel pressure ??) I see on various forums that deviations from the Long term trim up to 20% is not really a problem). While stuttering (takes only few seconds) I do not see any weird values.
what could be the cause

problem solved, after changing the spark plugs.
Some times thye solution is easy.