Ok so long story short, When i first got the car my distributor fried one day while driving and i never thought anything of it because of how old the car is and everything is original on the car, no cut wires or any garbage like that. Yesterday during an 8 hour drive from mississippi i noticed that when i turn on my brights at night the headlights flicker like an (on off) split milisecond thing, and sometimes the speedometer jumps down 20mph ( right when i flip the brights on) and then comes right back up instantly. I have a weak battery and am going to test my alternator but i was wondering if it could be anything else? Also after long periods of not using the brakes if i tap them after cruising speed the headlights would flicker. this has never happend untill last night. I have had an alternator die on me before and it doesnt seem like thats whats going on. Also when it sits idling and the fan kicks on the headlights flicker like the above description. Ive checked all the fuses and all my grounds are good and clean. Im trying to work all of the kinks out of the car but im getting stumped on these electrical problems, any ideas? Car is bone stock except for a pharable tuned ecu. Not showing any codes or anything, also no check engine lights or battery light etc.