2jz gte poping sound at idle and under 2100 rpm

[chase350z]

the set up
2jz gte vvti
mspnp pro ecu staged injection
440c primary injectors runs on 93 below 7 psi
2000cc secondary injectors runs on e85 over 7psi
wasted spark coils
6266 pt turbo on a cast fsr manifold with a hyper gate wastegate
i get a weird poping sound on idle and below 2100 rpms
its seems random and sounds like its from the last 2 cylinders
https://youtu.be/m4C8N4Lgb84
i changed the plugs and the coil pack still does it and with the injectors in thos 2 cylinders off it sill does it as well
any ideas are appreciated
thanks chase

just to and it has no problems under boost it spools stupid fast and makes good power.

[xgrapher]

Isn't that an exhaust manifold leak noise?