I tried that on my 260E. As you stand looking at the engine, the one on the right was easy. Just pull the air cleaner and the clamp on the idle air controller. The one on the left, that dives down under the intake manifold, is another story. I finally just convinced myself that the old one isn't leaking.
It may be hard as a rock, but my idle speed is down where it should be and nothing happens when I squirt a little carb cleaner on it.
Good luck,