i cant figure out whats going on with my egr. if i disconnect the vacuum line, and plug it, form it my truck runs great. if i connect the vacuum line up it will surge between 40 - 50 mph. i replaced the egr valve, egr position sensor and the evr vacuum solenoid. now the bok says to connect a vacuum gauge to the outlet port and a vacuum pump to the inlet port and the vacuum should hold, with the elect. disconnected to it. well it didnt hold and i went and bought another one and it doesnt hold vacuum either. theres another smaller vacuum/elect. valve next to it but this one im checking is the one in the picture, it goes to the egr. did i get a bad valve or am i doing something wrong.

 

Did you check the intake manifold EGR passage for carbon build up? It may need to be cleaned out.

 

i just had the intake off, did the intake manifold gasket, everything is clean and all the sensors check out.

 

Which manual are you using? I've got the Haynes. There's all kinds of tests in it. You can run the truck and apply vacuum to the EGR. The idle should drop.

 

been there done that, in fact you can do that with any egr valve, all the way back to the 70,s. strange thing is that even with the hose plugged with a ball bearing, if i put it back on the egr it will surge but less. i checked the back pressure and only have about 1-2 lbs. so i dont think it that.