Please take a look at the video. Every now and then I get what I can best describe as buffeting in the PMDG 747, and the PMDG 737NGX. The real issue is at low speeds (approach) my speed can drop to the point of stalling. This is running REX with real world weather. If I set weather to one of the themes it seems fine. The last part of the video shows where the aircraft will sometimes climb then descend outside of FMC / MCP settings for no reason. I have googled but can’t seem to find a solution.Thanks,Paul Humphries.http://www.youtube.com/watch?v=xtZL31yO3fI

Hello Paul,Your aircraft is perfectly fine. Your weather addon software however is not. It's creating a very bad case of windshear; you can easily see it on the standby ASI and also on the PFD with wind jumping in THREE !!! digits.Ionut Micu,Romania

If you have a registered version of FSUIPC, enable wind smoothing.