The intake manifold sits on top of the engine on four vertical studs. For whatever reason, they are slightly angled outward to the sides of the truck. I cannot lift it off of them no matter how hard I try. Any ideas? Is there a tool that I can use to straighten them?

Looked in my '02 manual and don't see anything obvious that might help. E-mail me with your e-mail address and I'll send you the Adobe file so you can look for yourself.

I got it. Apparently I just needed a break. Thanks anyway. Looking at the exploded view on EM-108 (that only shows two), I didn't realize that there was a third bolt at the base of the water neck going through the timing belt cover. I am an idiot!

No, not an idiot. I had a hell of a time figuring it all out when I took mine off too. The second time is always easier when you know what to expect.

why are you removing the intake manifold?

Had to change the knock sensor, was causing bypass mode. Fun!

Guess you missed the info about bypassing the stock one and relocating a Maxima sensor somewhere more convenient...
http://www.xterraownersclub.com/ubb/ultimatebb.php?ubb=get_topic;f=2;t=001042

I never searched "knock sensor" in drivetrain, so yes, I did miss it. I'll try the relocation next time. Hopefully it won't be for another 95,000 miles.