I had the same problem in my 93 2.3L. The engine would die when i would put it into park after driving for a while, and eventually started to stall on the road at very slow speeds. The problem was a bad fuel pressure regulator. It wasn't a cheap fix, but i brought it to a dealership. I would imagine that it isn't a difficult fix for a more knowledgeable person.
There are no wind speeds to discuss on Mercury, since there is no atmosphere there.
There is no wind because Mercury has no significant atmosphere.
Have you checked to see if the elect. fan comes on ?
Not running on all cylinders? Bad harmonic balancer?
On the Ford 4.0 liter OHV , V6 engine the PCM starts cutting the fuel back at 5200 RPM in order to protect the engine when it is IN GEAR I believe it does it at 3000 RPM when there is no load on the engine ( park / neutral ) ( if that is what you mean by high speeds )
Mercury is the 'speediest' planet because of it's fast rotational speeds.
If it happens only at idle speeds I'd suspect it is low on freon. If it's intermittent at all engine speeds there may be moisture in the system affecting the expansion valve or a problem with the expansion valve itself.
light or soundtime
acid speeds off proccess
Engine rough book
If you are driving under 30 MPH it probably won't do much damage, but shifting to neutral at highway speeds and you will ruin your engine. If you start skidding on an icy road (probably going 20 MPH or less) shifting to neutral will take you out of the skid and stop your vehicle immediately. Doing this spared me from colliding with another car when I was skidding in snowy weather.
The variable intake controls the amount of air pushed through the engine in order to keep it from stalling. The laws of physics that describe Air flow at speeds below Mach 1 (speed of sound) are different for air flow at supersonic speeds. So the size and shape of the engine inlet at low speeds are different that at high speeds.