EGR flow malfunction P400

I posted this as a reply to an idle but I thought it might help in a post of its own.Hope this helps I just pulled the engine out of my 96 to replace all the oil seals and at the same time I fixed this problem with mine. It also had the check engine light on with the EGR flow malfunction P400. I took off the upper intake where the throttle body connects and You would not believe the carbon on the back side of this it looks so clean on the front side and on the inside at the back where that small pipe goes from the intake to the EGR was stopped up with carbon. I took carb cleaner and cleaned out all of the metal lines that vac goes through from the intake and that tube to the egr and I took the egr off and cleaned out behind it also. Put over 200 miles on it this week and it is perfect now with no ac on. I got my info from this page http://www.asashop.org/autoinc/feb2005/techtips.cfm

It didn't make much sense till I got into it but this man knows what he's doing. I'm sure this can be done with the motor in but I had to replace the seals so with it out it made it so much eaiser. I think this will help I had the same problem. Well worth the trouble.