I have been experiencing some issues with my Jetstream 41 when ever i do a flight into an area with custom scenery eg Andras field by aerosoft or sometimes places that are default parts of my plane begin disappearing or the scenery textures go hay ware or both. I don't know why this happens, im running 6 gigs of ram and have 80 or something GB free on my Hard Drive. This also happens if i go in to the map view and then click out of it. any suggestions.

How much graphics card memory do you have? Do you have the HIMEMFIX=0 statement in your FSX.cfg (see pinned topic on graphics in general section).