the effect of the VSS besides for the cruise control and other various EEC things is to keep the idle up, while the car is in motion. to test it, when car is idleing in the driveway, blip the throttle a few times, or even hold it at 1500, 2k for a couple of seconds. let off of it and then the rpm should then drop back down to whatever you have the idle set at. next, take it for a drive. just do a couple of 1-2 shifts,then push in the clutch or just put it in nuetral. the rpm should stay up above 1k. when you come to a stop, after a brief moment the idle will come back down. reason is the VSS is reading that the car has stopped, and thus not needing the extra rpm's, it goes back to idle mode. another test is go on the hiway or a long road and get speed up and then coast as long as you can/want. as long as the car is moving the idle is going to be a little high because the VSS is detecing motion. if you try to "blip" the throttle like in the carb car days of warming up a car, the idle will still be high. but when you come to a complete stop, then the idle will come back to normal. if this is what is happening, nothing is wrong and the VSS is doing it's job.