We currently offer a massive range of downloads for FSX, as well as older flight simulator add-ons for the ever-popular FS2004, FS2002, CFS3 and now becoming ever popular with dediced virtual aviators is Laminar Research's X-Plane series.
To synchronize your engines, you need to tell FS which engines to synchronize. If you have two engines, enter "E 1 2" and whatever you do next will affect engines 1 and 2. If you're in a 747, use "E 1 2 3 4" and you will be controlling all four engines.
If, for some reason, you want to control only one engine, use the same command. "E 1" will put you in control of engine 1, but not engine 2.