'97 Avalon strange flickering headlights

I'm searching everywhere for an answer to this weird problem, haven't found one yet.

-Headlights start flickering very fast, but -only- above 55mphish, continues until I slow down.
-Dealer replaced battery, said nothing else wrong, now out of warranty.
-No flickering below 50 or so.
-Bumps, etc. do not start, interrupt or stop flickering, which is intermittent but continuous every two seconds or so.
-Flicker is very fast, not like something loose.
-Revving engine to 3000 or so while in park produces no flicker.
-Reseated all relays, fuses.
-Taped down all wiring in case wind caused something to short.
-Searched web for recall/notice but found none.

Again, I can drive around town at below 55 or so, bumps, wet, dry, and lights rock solid steady. Sounds very mysteriously electronic/computer in nature due to the point it starts, and the consistent pattern of the flicker.

Have run out of ideas, and hate to take back to the dealer. I know they're going to start replacing things for $$$$ until they find it.

Any thoughts or advice would be appreciated! Thanks!

John

Maybe the bulbs themselves are bad? I've also heard about the electrical harness that the lights connect to shorting out, getting wet, and going bad.

Why don't you see what rpm you are running at 55-60 mph. Then while parked hook a volt/ohm meter on the battery, have someone rev the car and hold it at the rpm you found. See if the voltage varies at a constant rpm and see if you lights are flickering. I suspect you will find trouble in the alternator/voltage regulator system. One other thing to check is the ground side of your system. Clean all point with a wire brush on the negative side. This is the easiest and quickest thing to check. Hope this helps.

Was wondering if you found what the problem was with your flickering headlights, we have exactly the same problem....