06 tacoma voltage issues

[Gilbert Garcia]

i have a 06 tacoma with some voltage drops i have never experienced before.

so a few weeks ago i noticed my hids would flicker or not power on at all ,so i checked my voltage at idle and i had my system off meaning stereo and amps i had a pretty healthy voltage just about 13.5-.7 and as soon as i turned my system on i saw my voltage would drop to about 12.3-13.1v depending what my bass level was ( i understand that the more bass the more power drain but after a few songs i noticed i would get something like 7-8v and my lights would flicker or power off. i received a suggestion to use a cap but i did my searching and found a lot of ppl did not recommend caps because they also cause voltage issues for the amps.. so i looked up the big 3 set up and im willing to try and attempt this but i had a old school installer tell me it would not have any effect on my issue so now im just not sure what i should try/do

just incase anyone is curious

i have an kicker 350.4 for my door speakers

i also have a jbl gto 501ez 770w mono block amp for my rockford fostgate power t1 10"

my wire set up is this :

i have my power wire (4ga) running from bat to a disto block then i have 8 gauge to the kicker ground is also 8g and 4 gauge to the jbl and ground is 4 gauge solid grounds contacts are bare metal

i just dont understand why im getting this issue im not running anything to power hungry at most im guessing less then 1000 watts running on a stock power system what would help i can post pic tomorrow if needed ..

help please

[SLYentist]

Check that the stock charging system is actually healthy first. Turn the stereo off, headlights on, defrost on, heater on, check the voltage then. If you see anything below 13.2 volts, your alternator is suspicious