Hi Everyone- I have been struggling with a hunting idle issue for a long time. I seemingly got a little closer to fixing the problem.

The car is in perfect working order. It has a rebuilt harness & throttle body and nearly everything under the sun that would normally make a difference with this issue has been replaced.

I plugged the vacuum line leading to the EGR and the car idles normally. I figured it was the switchover valve on the front of the engine. My buddy gave me a number of spare to try out. None of them made any difference at all. Once I applied the vacuum hose to the EGR valve at the back of the engine it started stumbling again.

Is there supposed to be vacuum at idle to the EGR? There is a strong amount of vacuum coming from the metal line that routes to the side of the valve cover. I am wondering if this is normal?? I am not sure if there is supposed to be the vacuum at idle and if there is does that mean the EGR valve itself is faulty?

Thanks in advance