DID SOME CHECKS
I found the LED indicator in front of where the battery would be if it was in the front of the car - when I pushed the buttom the LED on #4 illuminated - no # of flashes, etc., just the number 4 slots lights up. Using JimF's link to a web site, I guess this means the "air injection system" is faulty, is that correct?
Searching some of Arthur's posts, I decided to check vaccum lines with my Mighty Vac - I cannot get vaccum on the main vaccum line coming out of the intake; I checked the EGR and it definitely is working (engine stumbled, etc.). I tried clearing the code with various methods mentioned in the posts (held the buttom for 4-30 seconds with the ignition on; held it down for 30 seconds with the ignition off) but no joy. Finally disconnected the battery and that cleared the check engine light.
Does it sound like a bad main vaccum line? Although the rubber ends look fine, I can't tell if the hard plastic line itself is bad (although being unable to get suction probably means it is bad) because it's sheaved in another plastic protector.
What I thought I might is just get a section of vaccum line temporarly between the intake and the "Y" joint over by the windshield washer tank. Any other recommendations?
I'm going on a little drive with my wife tomorrow and maybe I can get it to repeat the "roughness" she has described.
As always, I appreciate the help from everyone.