Id check the idle speed controller.
Its near the throttle body, and basically the thing controls the cars idle, as well as blipping the throttle when down shifting gears in the auto (Kinda like heel toeing a manual).
This thing can get a little grease and oil in it, (especially if you are running K&N Filters).
Mine starts to stick every 5000K's, so I am always ripping it off, and cleaning it out.
I am fairly certain that this is your problem !
Check out this page. I know the pics are from an EF, but the same Idle speed controller is used on the EA, its just mounted upside down (I think from memory)
Hope this helps