Since i installed my throttlebody and plenum i have noticed when the car is completly warmed up and at idle i can hear this sucking noise kinda. Not sure but thats the best way to discribe it. I can't find anything and the car is running fine. Anybody else have this?
Try opening up your hood when you start hearing that sucking noise and looking for where its coming from. It happened to me and it so happened a line collapsed and was making a real loud sucking noise
well i just installed mine & did everything right, BUT the line on the back of the plenum came loose on me & it sounded like i had a cam the size of my head in there
another thing is, check the gasket inbetween the plenum & tb. my gasket had a weird cut out in it to match the TB. well the stuff didn't line up exacty so it cause that sucking sound as well. i went out & jimmy rigged it until i can go to the parts store & get a bigger gasket to cut down to match it.
Is your idle steady? if not check the plate/valve inside the TB to make sure it sits fully closed at idle. if that doesnt work then take the hooker out of your trunk