I recently had a vacuum line replaced due to there being a leak. Prior to the replacement, i was running about 7-9psi. After replacing the line, i found myself running 18.3psi in 4th gear. I know thats definitely higher than what its supposed to be. Anyway, as i let the rpms climb, i noticed that the boost would build to 18.3, then suddenly dip down to 9.8psi for a second, then fluxuate back to 17psi, 9psi, 18psi, etc. Anyone have any ideas on whats going on here? Thanks for any help.

Heres my info:
2002 WRX
HKS DP/UP/CBE
AEM Intake
Cobb AP Base Map at Stage 2 91Oct, but Real time map at Stock married mode at time of testing.