Check engine light, rough idle

[YahaAnt]

So, my cars always had a rough idle. Sitting at 700-800 rpms,
shaking a lot, whole car and steering wheel.
so,
last few times I’ve taken the highway.
if I hit 80 or steadily go 70, it cuts the check engine light on.
and then when I come to my next stop, it’ll drop rpms to like 100-200 and it honestly feels like it wants to stall.
I haven’t given it the chance too yet as I always just put some gas down and hold my brake while doing so.
I’ve finally come to a full stop with it on this time, it dropped in idles really hard, and I put it into park and it settled at 6-700.
i have recently replaced,
battery, alternator,
main relay,
plugs, wires, distributor + cap,
fuel pump is brand new just done a week ago.
(this issue persisted after replacing the pump).
I have a dB audio 12’ sub in the trunk running a amp,
and some Sony’s in the rear and Focal in the front,
i have noticed when the bass really hits my rpms heavily drops as well.
wondering if this consistent playing of music loudly has run extra wear on something.
but I’m so lost and I haven’t got a mechanic with the time to help me check things out.

[Sleezycb7]

Those engine lights will be saved unless you have had your battery unplugged or rest your ecu in between them coming on, in order to check them you have to jump a two wire harness in the passenger foot well. Ho under the dash on the passenger side, right in front of the door there is a plastic cover that pulls out, the kick panel. you may have to use some force, once out it will reveal a connector that is not connected to anything, jump this using a wire or paperclip, anything conductive, and turn your car to the on position without starting it, the cel will blink in patterns for each code with a long pause between each code then repeat. Each long blink is the first digit, ie two long blinks means 20. Each short blink is the second digit, ie one long blink then two short blinks mean 12, this would be an egr code. You can look up the code list, or reply here and I will respond with what the code means and some troubleshooting possibilities. Also the rpm dropped with heavy bass hitting is normal, the ecu will learn the power draw and compensate somewhat, just like the ac. My car does the same thing and I have three amps. But depending on how much power you're pushing you may want to upgrade the alternator, stock is only 65 amps.