Hi, I don't think there's a month goes by without my X10 setup doing something unusual. This goes from missing the odd signal to completely baffling scenarios, where one light turns on when another turns off.
I struggled for years until I finaly got round to using an X10 meter. It's a signal generator and receiver. You plug the generator into 1 plug socket and the receiver into various others.
Using this I found that the signal strength varied hugely throughout the house. And not in any logical way!
This gave me the information I needed to place my TM13 in the best position. It also gave me information on what things cause interferance. I then filtered the noisy items and the system is far more reliable now.
The only problems I've had in the last few months are because I havent read the manual!
Hope this helps.
franktate