Erratic brake performance due to rough idle?

[WestCoastSVX]

Totally throwing a theory out here.

I have noticed lately that occasionally when I push the brake pedal it will seem to "slip" a little? Very hard to describe. It will start to feel normal, then the pedal will almost feel like it is dropping suddenly to where it is not a smooth push. That's the best I can descibe it.

This is always at very low speed, like navigating a parking lot, and it's never resulted in poor brake performance overall, the car still stops where I want it to stop. But again, we are talking about < 10 mph here. It's never done it at any higher speeds, which is good for safety, and also lends towards my theory.....

Another thing is VERY occasionally, like maybe 1/4 of the time it does the above symptom, it also makes an audible "electronic" type of buzz for a second. Again, hard to describe, but almost like a little pulsing buzzing sound? About 1 second total, and always with that erratic brake behavior (although again, the sound only happens about 1/4 of the time).

I've had the car into a trusted shop to check on some things, this included. They went over the whole braking system and couldn't find anything visually out of place. It's not like they tested the sensors or electronics, but all the physical components looked and acted as they should (and of course on the test drive nothing acted up as usual!). All rotors and pads are brand new, as well as fluid flushed with new. Stainless lines and calipers are at about 20K miles.

So now my theory/question. Could the electronic braking system in the SVX be affected by the rough idle issue I have? At stop lights and low speeds I do have issues with rough/fluctuating engine performance, which I'm working on (probably will do new TPS next). Could this possibly affect the braking system, like is it RPM sensitive, or maybe cause a power drop that affects the electronics? Or am I dreaming and should have a more thorough inspection done on the braking system electronics?