Full boost in first 3 gears..then half in 4th!
 

Anyone have any idea why im getting 13psi in 1st 2nd and 3rd and then only making 6psi in 4th?
It seems to only happen when i pull from 3rd and then go into 4th.
It doesnt happen when i start from 2000rpm or so in 4th and go WOT.
Factors to consider:
Silencers in otherwise open exhaust (but i really doubt thats the case)
Greddy ProfecB was tuned in 3rd gear (usually reccomended to tune in 4th..but its not a fuzzy logic controller!)
any suggestions?
TIA