Ej swap idle issues

[MrTong]

Ej22 uneven idle
Hey guys, Having some issues with my Ej22 (obd1) (motor has been rebuilt about 3 months ago) swapped Subaru L Series after the car sat for about a month. Started with needing a jump, but now I'm chasing a few weird symptoms. Only code I get is code 33, which hasn't hindered running since the swap.

Harder to start when warm (cranks ~5 seconds) Rough idle that smooths out when throttle is applied
Exhaust has a "misfire" type sound at idle
RPM takes a a few seconds to drop back to idle after revving
Occasionally shakes a bit when shutting off or at idle
While driving, revs seem to hang/stick around 4000 RPM, then suddenly get better after letting off slightly Feels like a "dead spot" or sticking point in the throttle, I've cleaned both the iacv and the throttle body and it seems to be a bit better but that 'exhaust misfire' sound is still there.

Anything else worth checking? I have a new MAF sensor waiting to be put in, before the car sat for a month everything ran fine. Can get videos of it running when I'm back t the car later today.

Cheers