How to check EGR Valve?

[ponkotsu]

Still chasing down rough idle issues...

I connected my scanner to the Aviator. Sprayed carb cleaner on the EGR valve and got the short term fuel trim to drop almost 10%. Seems like a leak. Note, this does not have any audible change to the engine because the computer does such a good job of compensating.

I then took it off and took a good look. There are two vacuum ports. One is vacuum supply (top) and one is downstream (bottom) for measuring pressure delta. I applied vacuum to the vacuum port and it leaks pretty good through the vent filter. Holding my finger over the vent hole stops the leak and then allows the EGR to open. Not sure if this is normal or not. Anyone know? Don't want to spend $100 on a new EGR if I can avoid it.

EDIT: This is one of those integrated EGR modules with the valve, sensor and solenoid valve all in one.

 

[ponkotsu]

As a side note to this, I did disconnect and plug the two vacuum lines going to the EGR module to see if it improved the idle. I think it did for a short time but then went kind of haywire. The MAP sensor is part of the EGR module. So the MAP sensor is erratic, switching back and forth between full vacuum and atmospheric pressure. I don't know what the ECM does with that data but it can't be good.