FRKWOO

just got another 98 ek hatch 5-speed and i had a spare 5-speed z6 manifold laying around so i decided to swap out the y7 manifold with the z6. so i did the usually took off the y7 manifold swapped the z6 with the y7 tb with z6s throttle cable "pulley" connected all the sensors cut and spliced one of the IAT sensors so it would fit the z6 IACV. finished connecting all the hoses and when i went to start the car everything was fine but when you rev it the motor sounds like its struggling to take in air it revs then idles low then does back up and will evenually died out....what can be the problem?