loss of power below 4k rpm

[jed344]

Tonight driving home i noticed my car was lacking in power but here is the wierd part. below about 4k rpm it had no power will put it to flow hear open dump and turbo will spool up to 15psi i have it set at but almost like e brake is holding it back then after 4k itll take off like a rocket. its been cold and rainy and i noticed it did it once before. Any ideas why? My ecm link comes in tomorow so ill datalog it then and see if anything shows up.
mods list
intake, open o2 dump, 3in dp, 3in catback, walbro 255, ffwd fuel kit set at 52psi fuel press, 1g bov ( recirculated not vented) 14b turbo.

 

[CLEANest98GSX]

Sounds like a boost leak. Do you have an aftermarket vaccuum/boost gauge?

Yea this same thing happened to me. My vaccuum was at like 10 compared to where it should be which is like 19-20. At low rpms it would barely go and if you kept holding the gas all of a sudden it just takes off. I would check vaccuum lines. I couldn't tell you exactly how I fixed it because it kinda just fixed itself. DSMS are like that unfortunately.