Good to hear that you found your problem.
I, too, have had the same problem and I also replaced that Y boot. That being said, access to it's hose clamps was not fun.
There is the big clamp at the intake and the small one on the branch that connects to the Idle control valve.

To do this, I recommend that you remove the air box and the intake hoses that come from the box.
Then, remove the recatangular black box which is called the plenum switch (I think). It has two hex head screws that secure it.
Then remove the screws that secure the idle conrol valve and pull its mounting bracket out a bit (dont remove it, just pull it to you getting it out of the way)to get better access.
Then, you can see the hose clamps. There was a problem with mine, maybe for you too. The screw heads of the clamps were facing down. That meant I had to get under the car and snake my arm through to get to the screws. I recommend using a socket to fit over the screw head and forget using a flathead screwdriver. It will simply slip off.
Once you loosen the two hose clamps, you can pull the boot off the intake. Note that the branch portion is secured to the idle control valve. And the ICV is pressed into the intake manifold by a rubber grommet. I tell you this because if you pull the branch off the ICV and pull the ICV with it, you might pop it out of the grommet. No biggie, just be aware.
Installation is the reverse