How important is the EGR valve to proper functionality in the ECM? Mine is bad and it's vacuum line has been plugged now for several days. It doesn't seem to care. Since there is no way that AZ is going to let me tag this thing anyway, I'm thinking it might be better just to block it off and call it done forever more. On another note, who the heck came up with the design on that stupid thing? Why is it that smog junk is always odd-ball, hard to work on, and invariably in the way? Both nuts are completely buried by the diaphragm and access from the side is blocked by the TBI and a whole rack of sensors/solenoids. Looks like I'll have to pretty much strip the top of the motor just to remove those two @#$# @#$# nuts to replace that thing. I generally don't subscribe to conspiracy theories but, I swear, this smog stuff fits the bill. Difficult to maintain/test without specialized tools, smog laws that have absolutely no basis in reality or real benefit, etc. You could have far less emissions than the car in the next bay but, if you don't have a functional widget, you fail and they pass. What a load. Russ 85 K30 CUCV, 350 TBI, TH400, 205, D60/C14, 4.56 Locked Some day: 4" lift, 44" tires, massive cutting, shorter wb and rear overhang.