Tweaks to the fsx.cfg file can be very useful, but can also result in strange behaviour when FSX is pushed farther. ILS systems may not work, you may get crashes, you may not get proper winds, you may not see all the textures, and so on.
When you have IF running, FSX has to send a small packet of information to IF, other addons, aircraft, and guages may also be doing this. Eventually, as you add functionality to FSX, and you have trweaks installed, you may find the bar is lowered and the working set of tweaks now causes problems.
In this case, put your fsx.cfg back to defaults and then, if you wish, start the tweaking process again, and find the new setup.