Hello, my 737-800NGX fly S-Turns in the LNAV mode by light turbulence, if the turbulence end the plane fly normaly without S-Turns.What can I do to prevent the S-Turns? I use the Active Sky Evolution weather tool. Please help. thx

Check out ASE's help page (in ASE) and follow the directions for PMDG aircraft. That generally does the trick.

I had to disable turbulence effects on aircraft. Same thing with the Level D 767.

ASE manual advise to either disable turbulance effects through FSX settings, or if u would like to see some turbulance effect just set turbulance effect to 0.5 (from 1.0) in fsx.cfg. I set it to 0.5, DWC enabled in ASE and no more S turns for me.

PMDG also say to disable turbulence and thermal effects in fsx, as it creates a vacume around the aircraft.