WOW we didn't get away from the problem of flickering lights by chance did we????
My guess would be to goose the engine off of the idle and see if it takes care of that. I'd check the ground at the radiator support but i'd also check the grounds in the turn signal lamps up front. The bulb socket in mine was loose awhile back and was causing mass hysteria to my truck!!! Everything was blinking when it wasn't supposed to be!!! If you're grounds are good well then I'd just hook the multimeter to it and check your volts. If the volts thats go to your headlights fluctuate well then it ain't a ground on the lighting side. More than like an alternator or something of the sorts