[fsurfer]

Since disconnecting my battery and reconnecting, this inturn reset my ECU plus all other electrical add-ons.

I have a smooth running engine, a responsive sub-woofer (at a lower volume) lol

Earthing??

[Leeky]

Nope, just sensors and ECU's being reset to default settings and self-learning (where applicable).

If it was earthing, it would do the same once reconnected.

[fsurfer]

True, however I was looking at from corrosion on the battery posts