egr system/knock sensor problem

I started a post yesterday titled "help, I nerver get a response" just to get some attention (no I didn't mean to spell never wrong). Hopefully with a better heading I can get more info. I have a 92 Maxima SE w/ 127,000 miles, manual transmission, doesn't burn any oil. I changed the knock sensor a while back along with spark plugs, pcv valve, air filter, and oxygen sensor, and I cleaned the upper and lower plenum out really well when I did the sensor. Should be runnin great right? Wrong. It still shoots a knock sensor code so I must conclude that it is knocking and the sensor is just doing it's job. I just want to know if the EGR system has anything to do with this as I read somewhere that if it is not working correctly it will raise the temp in the combustion chamber or something like that and cause a pinging and knocking, both of which my car is doing. Any info would be great. I also noticed that the front bank of passages when I took the lower manifold off were very dirty and the back ones almost spotless. Why? I cleaned the EGR valve out today and noticed no difference. I am very disappointed with the max right about now. :disappoin