Opening Throttle Does Little To Nothing?

[ANVIL]

i just upgraded my intake manifold to an ISIS unit (greddy style) and used a q45 throttle body with it. i have everything hooked up correctly and the car idles pretty good but just having a problem with the throttle. when i open it nothing really happens. what can cause opening the throttle to give no effect to the engine? also i swapped over the rb25 TPS to the throttle body.

[ANVIL]

also my EBC/boost gauge shows im only having 6-5psi of vacuum at idle.. isnt it supposed to be like 16ish?

Edited April 7, 2009 by ANVIL

[femno]

Vacuum isnt in psi, its Hg. (Inches). You probably have an airleak somewhere if you have only 6 odd.

Do you have aftermarket management?

Because youve just slapped on a huge throttle body, and the plenum runners are much shorter, the standard ECU wont be able to cope, and will most likely give you a nice and heavy flatspot (which is what youre describing) due to the increase of air volume from the bigger TB.