Thank you Moses the diagnostic port Diagrams were very helpful. I just have one more question. I hooked up a Snap on MT2500 scanner to my 89 jeep yj and everything checked out and read "ok to drive" but the EGR valve read "open" the whole time the engine was running at idle(idle read 880 rpm) and i removed the vacuum hose at the EGR valve with no change to the reading. Shouldn't the valve read closed at idle?