Idle and fuel problem, running rich

[capatown]

CAR - AE86
MOTOR - smallport 4age
USE - drift/street
PROBLEM - At idle car revs from aprox. 1000rpm to 2000rpm constantly, pretty sure car is running way too rich
OCCURS/STARTED WHEN - Possibly from a bad batch of fuel ? maybe not, just happened.
PERSONAL SITUATION -Tried adjusting the timing, it made no difference at all. Put a new fuel filter on, still the same.

Im pretty Sure it's a fuel issue as it's not missing at all, ive played with the timming and it doesnt make any difference at all.

Im not sure where to look next, could be a vacum problem ? Or maybe the ecu has gone into some weird limp mode ?

It's running rich for sure, nearly like its surging, heres a little video of it idling, like I said im not sure what to check next.

Any help would be muchly appricated!!!!!