So i currently have a weird issue at idle and low load. The engine is bouncing from 800-1000 rpm (1000 - 1200 when cold) idle and when you turn the throttle a hair you can hear it struggle.
The issue persists while driving and barely giving the car throttle (stuttering and the car shaking a little due to engine stutter). But oddly under heavy throttle the car runs perfectly and is
very responsive. I originally thought this was a IAC issue, since i have had a faulty IAC before (around 60k miles ago) and figured hey, maybe it just went bad again. I replaced the IAC today
and the issue still persists.

A little engine history.

188k miles
Top end of the engine rebuilt @ 136k (heads reworked and everything) due to water pump seize and timing belt walk (boom 6 valves and 12 valve guides totaled)
IAC replaced

Heres a video of me starting the car, letting it idle, giving it a little throttle, and showing the hesitation.
Excuse the dirtiness, i just got the car out of storage and having had a chance to detail it.

Could this be a vacuum leak? or is it more likely the ECU has bad caps.

Any insight is appreciated.