I hear ya!
well It sounds like you are on the right track. Heres how to check for codes.
http://fordfuelinjection.com/?p=13
And so you know, I found my problem. It was an exhaust leak. Before I went through inspection I checked it out and found that I had a pin hole right at the bung of the O2 Sensor. It was my fought since I tig welded a new one on a few months ago. That wasnt the whole problem though since it did it BEFORE I ever touched that O2 Sensor..
..The flange where the y pipe meets the cat was leaking like crazy. I knew it was leaking but I didnt realize how severe. So I took it down and noticed it was pretty warped. So I put it on a a 90 degree angle belt sander and leveled it out. Now all is well! Its been a week and now its fine. It took a few days for the computer to notice the change and run better but now its fine.
Hope that helps man. Check for exhaust leaks..especially around that O2!