I feel kinda dumb asking this, but can anyone tell me if there is supposed to be a hose connected to the circled area. Picture is from the top of motor, driver side, and the area in question is directly adjacent to the motor side of the throttle body. It looks kinda like it should have a vacuum hose attached to it.

The port in question is facing the firewall.

The reason I asked the question above is this-
Today, I cleaned my throttle body. Disconnected negative battery terminal before starting. Got it all nice and clean. I hooked everything back ip and reconnected negative terminal. Now, the motor has a faster idle- throttle almost asked like it'* sticking. The DOD is not the same at all. Almost as if it had been deleted. Motor used to drop to idle when driving and letting off the gas. Now it stays at about 1000rpm until I stop, then a second after I stop, it drops to normal idle. It does seem to accelerate alot faster, but it also just doesn't feel right. I double checked all the connections that I unplugged and everything is back as it was before I did the cleaning.
Anyone have any insight as to what might be causing this issue?

Well, what you should do, is disconnect the neg cable first , and then the positive cable(key out of the ignition and nothing on).......now, attach both cables together for several minutes with a jumper wire......this resets all modules.......then reattach positive cable, and then the negative cable and see if that takes care of the problem....

If it doesn't scan for codes....

Also, should post the model, year, and engine size to help in diagnosis....

The car is an 06 Grand Prix GXP 5.3 V8 w/DOD.
I will give your answer a try. I did the basic relearn procedure and the car has relearned the proper idle speed when started and when stopped, but still having some rpm issues, so I am going to check for vacuum leaks first, and go from there. Will probably replace the throttle body o-ring, which I should have done in the first place. Before I finish, I will use your jumper wire suggestion just to make sure. Thanks for your help!