Ok, the O2 sensor is fine. I cleaned the EGR, and I noticed in the chiltons manual that it says if you compress the valve and put your finger over the vacuum line hole that it should take up to 20 seconds to fully refill itself (move back to uncompressed) Well when I tested this it doesn't move at all. Could this be a problem?
First, determine (using the part number on it) if it is a Stock OE EGR valve. An AC-Delco/Delphi part, a "real" one. Then, if it is, determine, again using the part number, if it is the "correct" one for your rig. AC-Delco makes two, one for the manual transmission-ed rigs and one for the automatic transmission-ed rigs. A previous Owner may have stuck the *wrong* one on there, being sold a bill of goods by an unknowing (ignorant) Parts Geek. If it is the correct part, an AC-Delco, but for the wrong application, then it will never "work" right.
The Aftermarket EGR valves often do not work, brand new, right out of the box. The "normal" state of operation on these valves is closed. The EGR valves made over-seas do not have an adequate (strong enough) internal spring to keep them closed at idle. It is a catch22, it is good but not good. Being open a bit at idle causes all sorts of goofy idle speed problems as well as adding black, gooey, carbon to the insides of the intake tract. This, in turn. blackens the temperature sensor (IAT) and fouls ITS' readings, compounding the problem. A bad situation, getting worse by the minute.
I would not trust the Chilton's Book to tell me how to test the OE EGR valve. It is a "bass-ackwards" application, being a negative backpressure valve, which is exactly OPPOSITE of how 99% of EGR valves work. I have yet to learn how it is tested, "on the vehicle" as even my GM, S10 Service Manual is un-clear on how it is done. It is kinda one of those things where, if suspected of being bad, it is simply changed out.
I cannot figure out "how" this system works...does the EGR valve solenoid fire all the time (pulses), or just when the road speed is constant above 40 MPH?? At a constant road speed of above 40 is when the system is "tested" by the OBD1 brainbox. It calls for EGR valve solenoid vacuum to be applied, to open the EGR valve. The O2 sensor then "looks for" a lean-out condition and if none is found, the SES light comes on, and it sets a trouble code.
The whole of the issue is a PITA....