I have a 98 E-250 w/4.2 engine. I am getting the P1408 egr out of test range. I have checked the egr vacuum regulator and it is working as it should. I also checked the egr sensor. All are working as they should. I checked voltages and they are all in spec. I put vacuum to the egr valve and the engine does not change meaning no stumbling or anything. I pulled the valve to check it and it is working properly. Anyone know what the problem could be. Does it mean the intake will have to come off to clean the exhaust ports? But I don't understand why the engine is not stumbling when I apply vacuum to the egr valve.

 

If you can put vacuum to the egr valve and there is no change to the idle, then either the egr tube from the manifold is completely plugged, or the egr valve is seized. Can you move the valve diaphragm with your finger?

 

Well the EGR is working .I pulled it off and applied vacuum to it . I checked all the tubes to the EGR system and they are clear. I suppose that I have to pull the upper intake and clean the exhaust ports then.