I do not know Bob. That is the symptom I'm seeing. It has a hiss at idle, and until you call the 2*'s it runs normally. When the 2*'s should come on she starts to gurgle like it's drowning. I'll have to admit that I was not insistent on calling the 2*'s. As soon as I heard the gurgling I got out of the gas. I didn't even think to turn the key "off" and test it that way. I should have, but I just didn't think of it at the moment. I blew that one I know!
I was a bit distracted when I was doing a brief diagnostic in the garage where I park so I had to be quick as it was a bad time to be under the hood in the garage, too many people around.
I went back last evening & repeated the pump line test and it does hold vacuum with the motor off. I was going to start it up, pull the left vacuum line, plug the nipple and apply vacuum to that line....but I had bad timing again & there were too many people around again.
Soooo, my diagnostic plan will be to go bring her back to my building on Friday after work ( hopefully no rain! ) and test her with the key "off" and the key "ON" on the way over hoping that will give me some more info to narrow down my search. The hissing is, to my ear, coming from under the plenum as far as I can tell.
Tom