Revs Dropping Off When Clutch In While Changing

[maccaz_gts25t]

when changing gears at any time the engine seams to drop to aroudn 150-200 rpms sometimes lower then kick back up to 1500 then drop to 600 then slowly even out to idol ( if i put the clutch in while changing gears and hold it in) this then causes a back fire but only because of fuel build up....ne one got ne ideas..

ive ran some injecor clean through it and as thought did fk all... and also this will happen at most rpm's from around 2k up wards

running a 33 with t3/t4 high flow, fmic, bov, forged pistons, shaved heads, metal head gasket, mushroom pod, full trust zorst, power fc....running around 14 pounds

[R31Nismoid]

Put the stock BOV back on it, the most common of all issues.

problem solved