First, check you are using the latest vehicle updates. If you are not sure, just download and install the latest GSX Full installer.
If that doesn't fix this, it might be a problem of your graphic settings. Try all the following:
- Update your video driver
- Reset your video driver settings to default
- Reset the FSX settings to default, by removing the following file:
%APPDATA%\Microsoft\FSX\FSX.CFG
This will force FSX to rebuild a new config with all default settings. After doing this, be sure you apply the HIGHMEMFIX tweak in the Addon Manager, save the settings and restart FSX.
If this still doesn't fix it, be sure you don't run FSX into any of the "Compatibility" modes. Every checkmark in the Compatibility tab of the Properties for FSX.EXE should be off.
