5k speedo lag?

[Kurt Deschler]

My 87 5ktq has a problem with the electronic speedo where the needle lags 
the actual speed when decelerating. Once I reduce my speed by about 5mph, 
the needle starts to come down. At very low speeds, I also notice the 
needle pulsing up and down by a couple mph. Has anyone noticed a similar 
behavior or know a fix? I already checked all the solder joints around the 
speedo. This problem is not intermittent. Thanks.

 	Kurt
 	87 5kcstq
 	89 200tq
 	00 S4