Thanks for your replies and PMs.
I started cleaning the TB today only to notice that there is some carbon buildup on the inside of the throttle plate, but that the throttlebody is quite clean. Since I did not have the time to clean up the IAC valve, I decided to put the air intake tube back in and head back to work. Guess what? The idling was terribly rough all of a sudden.
Since the only thing I had done anything to was the air intake tube running from the air filter to the throttle body, I was amazed at how this could have suddenly occured. After a careful look, I noticed that this pipe had several cracks on it. I closed the cracks with my fingers and heard the engine smoothen out. So I put some duct tape where the tube was cracked and it ran smoother than I ever remember. Acceleration from a full stop was better than I ever remember (it had 143K on it when I bought the car) and I noticed absolutely no lurching. Granted, the lurching happens more frequently when the engine is cold, but I tried some of the other usual things that seem to cause the lurching more and more often, and still no lurching. Plus, I am enjoying the additional gain in acceleration.
I think the TB does not need any cleaning yet. But I am going to try some of the seafoam solutions I found on other threads. Thanks for all your help. And yes, I am going to install a new tube.