i have a forge vta bov and i have the green or yellow spring i cant remember, with no shims cuz when i had shim i would hear light surging, i took the shim out and perfect no surge or fluttering, ZERO, NONE!...for daily driving it works fine, never stalls out, perfect blow off during regular RPMs, but now a problem (PS: I have MBC 20psi)...when im on the highway in 5th and i floor it to WOT, about 3 secs later i hear a loud sputtering noise, and when i let off, it blows off late, i'll let off, it'll feel like the cars still having gas, and then it'll blow off late. whats wrong with it? i cant seem to fix this. in 1-2-3-4 gears if i take it to redline, it wont sputter or anything, it blows off and holds boost perfect. is it cuz i need a tune?