rx300 losses power (like no gas) for few seconds

[ed100]

when I am driving especially at higher speeds, my rx300 losses power for a few seconds then works fine for a few minutes again.

[Bruce Harper]

I seem to have the same problem on my 2001, although at varying speeds, and mostly while accelerating.  But it seems to only happen when my daughter is driving it.  When I opened the hood, I noticed that there is no bracket on the battery so it can slide around a bit.  I'm wondering if that may be causing a short so I will see if bracketing it in place makes any difference.