How do you remove the wiring harness on the front valve cover?

[ashcoal2000]

I've got a 2002 Sienna with a leak into one of the spark plug tubes. I want to remove the front valve cover. Toward the back of that cover is a black plastic box holding the wires that go to the cylinder coils and fuel injectors. In the manual, it says simply to remove the nuts holding this on. On MY vehicle, there are no nuts. There are round (maybe) nuts on these studs. I can't turn them with vice grips and they're round so there is no tool that I can think of that you'd use to remove them.

Does anyone have an idea how to get these off?

[TierOneSupplier]

TN member WISWIND who has an '03 Sienna has a very helpful set of photos with narrative which you can find here:
http://rides.webshots.com/album/576572371kcnZsT

This particular photo and its narrative may be helpful to your situation:
http://rides.webshots.com/photo/2591...11220610ThEWRP

The device you've described should come off with a couple of 4mm bolts -- look at wiswind's pictures and narrative and if that doesn't help, chime in and let's see if we can figure this out.

By the way, if you haven't found it already, this particular thread was a FANTASTIC help for me when I replaced leaking spark plug tube seals in our '98!
DIY: 1MZ V6 spark plug tube seals replacement 1MZFE