Do you have keyless start?
On my Focus you have to press the clutch down to start the car, maybe it is something to do with that?
The switch on the clutch informs the ECU that the clutch is pressed
On the Mondeo mk3 (and other Fords may be the same/ similar) it disengages the cruise control when you press the clutch
It also restricts or retards the power/ reduces the torque when the clutch is down, preventing the engine from revving, and from you slipping the clutch - according to Ford the reason is for smoother gear changes - i recon its to protect the DMF / clutch from rough gearchanges
If you by-bass this switch you will find the engine picks up better after a gearchange, - and pulls better from lower revs and you can slip the clutch when you want
Your gearchanges will have to be timed "perfectly" and you have to be smooth - it souts me as i have a silid flywheel/ carbon clutch with sprung plate, and a "short shifter" so gearchanges are more "direct"
I re-connect the switch when it is icy/ snow ("softer" power delivery - less liable to wheelspin) and i find i miss- time my gearchanges with the switch reconnected, as i am so used to the "feel" of it disconnected
In tests the 0-60mph etc was slower with it connected so disconneting it can be considered a "free" tuning mod (if you can get used/ live with the different "feel")
That will be why I can change gear better in the Focus than my mums 206.
I have always noticed the car dampens the throttle quite a bit, but your explanation clears things up a bit. :)
Shame you couldn't get cruisecontrol on the Fusion so that can't be the reason for the switch. ;)
The other reason is very interesting, if i look at the electric diagrams the switch is also connected to the engine ECU so i'm also gonna try to disconnect it and see if it makes any difference.
If it is indeed to prevent the engine from revving it's more some sort of anti dummy driver switch, maybe these days more cars have them but none of the cars i drove and drive have ever had such an switch.
Looks like Ford thinks we're to stupid to drive a car......................... :P