Do i need my VSS hooked up for my engine to run perfect. what i mean is, if i disconnect it, will the ECC run out of whack? and make the engine run worse?
James, if directed at me, that not really what I mean. The lack of the VSS connection will affect the rolling idle, so one might have to bump the idle setting a little to compensate (ergo use a higher static hot idle). Some guys dont like the rolling idle hang and tune it out altogether. I like it, but dont have issues [that some do with it].
If the VSS isn't connected, the computer will think that the car is going "0" MPH correct? So basically when you are rolling and press the clutch, the RPM's will drop below 1000. I don't know if that will cause any stalling issues... might even save a little gas by not reving higher when you creep to a stop.
The ecu's use VSS for different things in the cars. For example, in the SN95 cars, the ecu turns off the electric cooling fan when the speed exceeds 25mph. VSS signal is used to limit top speed in cars that have that feature. In the fox bodies, one thing the VSS signal is used for is to hold the idle speed a bit higher when you're decelerating. If you have a manual tranny, slip it into neutral and watch the tach. It'll hold it around 900-1000 rpm until you roll to a stop - then it will drop down.
My car has never had a VSS hooked up -- 10 years, 43k miles. Doesn't seem to have posed a problem.