Fuel problem or timing problem??

[boostedgst2984]

i just got my new head on and i am havin a bit of a problem with running smooth. in 2 and 3rd gears when i hit around 7-9 psi it starts to hesitate. But when i am in 4th and 5th it is holding 15 16 psi to high upper rpm's. What do you all think this could be a fuel problem or ignition timing. cuz i dont think its detionation.

 

[blackGSX2g]

Do you have a logger of some sort? That would be the best way to figure out what is happening. Do you have any fuel mods? Also, I'm guessin you upgraded to a 1g head (if not nevermind) but is there any problems with the CAS connection?