I ordered the VSS repair kit from ebay but I wanted to outline my symptoms and see if some other irregularities have been noticed by other members
I have all the regular symptoms: erractic speedo, sometimes check engine light, often D4 light is flashing. But sometimes (rarely) my tach will act a little erratic. I've had it where I've turned on my car and the tach wouldn't be working but the speedo would. I tried turning the car off and on a couple time and eventually the tach starting working....but then the speedo wasn't.
Another thing I've noticed with the speedo is that if I have the cruise control switch on (the dash button, not the steering wheel button), and the speedo stops working, usually turning off the cruise control light will make the speedo work again. If that doesn't work, pressing the button to roll the drivers side window up (only the drivers side) will allow the speedo to work. As soon as I stop pressing the button though the speedo returns to it's not-working state. And once when that didn't work, I pressed the button to cycle the air in the cabin instead of drawing in fresh air and that allowed to speedo to work normally. I've tested these again and again and they are very consistent in making the speedo start working.
It also seems that if you warm up the car really slowly, i.e. driving it around in 2nd and keeping it under 2k for 15 minutes, the speedo doesn't go erratic and the D4 light doesn't flash. Everytime I've had problems with the speedo and D4 light, I've found that when I park the car and stop it for 15 minutes or more (enough time to eat at taco bell) and return, as long as the car is still warm, I won't have any problems with the D4 or speedo until the car gets a chance to cool completely. Then my problems start up again.
I just wanted to see if all of this is indeed caused by a malfunctioning VSS.
Now to fix my overheating problem. The cooling fans keep blowing the fuse whenever they turn on. But only if the car is on.