The egr starts to open at about one inch of vac and fully open at 7 inches.Vac is applied from the svr to the egr. The egr is open to atmospheric though the svr in tell the the computer tells it to apply vac. There should be no vac at the svr at idle. There is a filter in the svr that you can clean but most of the time the filter is ok. You can test the evp to make sure the egr is closed at idle. As far as how much it opens you would have to put a tee in the hose and have a gauge where you could see it when you drive it. But not knowing the base line of it, it does you no good. Do you know what the base line is? I don`t. I would test the evp,svr and the wires going to them. Than check the tube and hose from the egr. Also pull engine vacuum. First thing is pull codes.

 

What makes you think it is the egr? Test the map and fuel pressure. o2 sensor?

 

It's a maf

 

I don't know if this will help but I made a block off plate for mine,so the ear opens and closes ,the ecm sees it working but it doesn't circulate the exhaust gas through,truck runs way better for it too

 

What symptoms would a bad evr be? It runs flawlessly with it unplugged

 

We have a mechanic up here that has done a whole lot of research on EGR issues with the 5.0L and 5.8L and he did some experimenting. His solution is he has made a blank metal plate the size of the EGR mount and drilled holes for the mounting bolts. He then get 2 egr gaskets and puts one on the engine side, then the blank plate, then the second gasket. He bolts this all down and reconnects all the tubes and hoses.

Ta Daa, the engine runs like a clock.

Just thought I would put that out there.

 

That is not a solution its a workaround for a defective system. Remember the truck ran well when it was new.

What you need to know is what is the EGR doing that is causing the change. The EGR should not effect the engine at idle. It shouldn't come on until cruising at part throttle no load, warm engine.

OK just looked up 212 and this is proving my point about workarounds. The reason your truck is running poorly according to the ecu is because it isn't getting any signal from the spark out circuit. Check to see off your spout plug is in place then test the spout circuit. Without that signal the ignition runs only at base timing. Fix that first then we can see if there is anything wrong with the EGR. When you use a workaround you ignore the actual problem.

 

What all should I test for the 212 code and how?

 

just delete the useless piece of crap EGR system.. it is useless in these trucks..

 

Not sure if it'll help, but regarding the sensor on top of the EGR Valve, it has been my experience that only a Motorcraft sensor will work on the Motorcraft EGR valve. If you have an aftermarket sensor, it will not work properly unless you have the same aftermarket brand EGR valve. That will cause all sorts of issues. Also, be sure you have the right sensor. There is a light gray one and a black (or dark gray) one. The light gray one is the one you need.