You may have other problems or the egr is half the problem. Did this just happen on its own? any work done lately on the car besides the IAC clean?

You can unplug your IAC the idle should go down or kill the car. Then plug it back in it should jump up. You can feel and hear the IAC clicking when you unplug it. Worth a shot. If nothing happens you IAC is stuck open/closed/ in the middle.

You may want to adjust your air bleed screw.

This is kind of strange. If your TP signal is more the .5 volts your ecm thinks you are on the gas a little. The ecm stops using the IAC valve and some time the engine falls on its face. The signal wire is the one in the middle back probe it with a safety pin and see what it is at.

A vac leak would cause a high idle so I do not thing it is that. A failed map senser would code. If it was a fuel system problem you would see it all over the rpm range. An ignition problem you would feel a miss. You can alway take a look at your plugs http://www.ngksparkplugs.com/tech_su...d.asp?mode=nml some times thy tell a story.

Thats about all I can think of I know you are good at this stuff what else do you think?