ev6rc: the HS-81 won't draw near the current that the HS-5925 will...
It will draw a lot of current if the end points are not set though...
The cap "Stutter Stopper" will smooth out PS spikes and also supply a small amount of current when the battery drops below the CAPS voltage....
A glitch in gas cars can be VERY hard to find......
Check these:
loose screws
low batteries(tx or Rx)
EPA on the servos(try turning it down to test)
Are you running a 4 or 5 cell pack?