My dad's 96 f250 with the 351w has a rough idle. The egr is getting vacuum at idle and a code for egr insufficient flow. The vacuum line was removed and ran fine but he wants the CEL to go away. With the line on, it goes away, but idled poorly due to it getting vacuum. Can I assume that the EVR is junk? Also, which port on the EVR is for egr and which goes to supply vacuum?

 

Yea sounds like the EVR based on what you stated. Did you unplug harness connector from it, make sure its not a electrical issue of some sort holding it open?

Vac line routing at EVR,

Green = top port (to EGR)

white = bottom port (from vac canister).

 

I did not. I will try that tomorrow. I had the vac lines right then so something's wrong, either the sensor itself or electrical