Sounds like the torque converter is unlocking and then locking back up.
> You can test this by driving at a steady speed and very lightly
> tapping the brake pedal. This will cause the torque converter to unlock
> momentarily and cause a slight increase in RPM's. The most common cause
> of this is a bad throttle position sensor. Other sensors and the brake
> pedal switch are also suspect.
[snip]
Thanks miles, I'll try what you suggest and report the findings tomorrow.
I forgot to mention that I observe the behavior at most any operating temperature or air temperature.
Another thing, would the TPS or other sensor problems show as fault codes w/o showing on the dash idiot lights as "Check Engine"?
Thanks,
mole