Disconnect the battery for 10-30 seconds. When you restart the engine it will run crappy until you drive it 30mph for a couple miles. What the computer is doing is resetting and gathering information again for air/fuel mixture and other things.
The ECM is behind the center compartment of the center armrest console. You have to remove the shift console to get to it.
You'll find 4 screws under the ashtrays for the shift console. After that you'll see the two screws that hold the center console. Unplug the cigarette lighter, pull out the console, and then you'll see it... the flux capacitor, I mean ECM.