My problem occurs while im simply driving down the road. My headlights, dashlights and all other lights will dim for a while then all the sudden they go back to normal brightness. I noticed that if im at a stop and give it throttle and it hits vtec they will brighten if they are dim and also if i flash the high beams they will go back to being normal if they are dim. What is going on here, could it be the alternator, i did a test and its normal any other suggestions?