idle rpm studder

[stikx]

2g awd it just suddenly started to idle studder after replacing the spark plugs and fixing the hose line going to the acutator.
Mods:
Safc
Big16g
fmic
8.5 mangacore
7es plugs

i checked the vaccum lines and they seem to be fine but i keep on hearing like an air leak near the surge tank below it or somewhere around it.
also the gasket on my exhuast to cat is bad can that cause idle problems?