The old valve had a bunch o' stick in it... It was resistant to compression by hand and by suction was tough. I have no idea if I'm installing this thing right. In other threads, people have mentioned snagging another linkage within the IP (?). I know that the valve arm is pulling on something. There is so little work room there that it is difficult to imagine it having to be more finesse than I have been able to manage (in the process I have felt it when it is seated but NOT pulling on a linkage).

The vehicle is new to me... I'm not sure about any one monkeying around with the throttle linkage. I initially thought that this might be a problem because the linkages weren't releasing very well. I lubed the linkages atop the valve cover and they seemed to move a bit better. I thought I read somewhere that the external linkages do not affect the shutoff valve.

A couple of times since the install (it has only idled in a garage - it hasn't been driven anywhere), the car shutoff (not consistently) after a 15-20 second delay. I haven't been able to duplicate this since. I guessed that there was some leaking going on in peripheral lines/fittings that I plan to replace. I then moved to isolating the switchoff... in my mind, it makes sense that putting vacuum directly on the valve would cause shudown, since that is what the ignition switch does.

I guess a leak in the newer valve is possible but not probable. It seemed pretty functional.