OK, we got all four of the O2 sensors replaced....

It turned off the SES light... yay!
It seems to idle just a little bit better.

But the sometimes slow start and rough idle are still there.

 

have you checked the fuel pressure?? may be worth a look..

 

You may have a pretty gummed up engine with the junk that was run through it. Try a thorough Seafoam treatment for both the fuel system and in the oil. you can get it at most Napa or other aotoparts stores. Add Seafoam to your oil and run it for about 500 miles. Then do a complete treatment for your fuel system and intake. My 5.9 in my 97 1500 was running a little rough at idle until I did this. I got a bunch of power back with smoother acceleration.