There is a discussion going on at the SOH FS2004 forum about a peculiar

PaulI have been experiencing the same problem but unfortunately don't have an answer. If someone happens to respond with a soulution would appreciate a copy to me.ThanksHank

Hi,I remember having this problem, and it usualy came about after pressing the E key on the keyboard (so close to the R key......).Don't know if thats a shot in the right direction, but perhaps its worth trying to re-assign the key for engine selection from E to something else.//Michael

Twins are about the biggest airplanes I fly so I've flow a lot in FS 2002-2004. So far I haven't seen any occasion where focus has gotten switched to one engine over another except for inadvertantly pressing the "E" button.Sometimes however getting back to both engines is difficult. You have to press the combination E+1,2 within a certain time frame. Way too easy to mess up. I have an X-45 stick so I just assigned one button (the Fire C on the front of the joystick) to E+1,2. Now any time I get the focus on one engine all it takes is one button press and I'm back. Haven't had a bit of trouble since.

That's NOT a "bug" in FS2004, but normally user error.Or a faulty gauge that does this.You must have hit the "SelectEngine" key (default: "E", or a simular joystick button) accidentally, which causes this. (Note: this also commonly happens with on-line flying/chatting" when the "E" key is not handled by the chatwindow, but by FS2004 itself)Solution: you can correct this by selecting all engines again via the keysequence "e" "1" "2"However, this doesn't work allways.Again, NOT a bug in FS2004, but usually a faulty addon gauge that continuously gives FS commands (which disrupt this key sequence).Note that the registered version of FSUIPC has an option to keep the throttles synchronised. Or program the "e" "1" "2" as a single key or button press, using FSUIPC's key/button programming mode.Rob