Gauge Problem
 

I recently installed white faced gauges on My 97, all of the needles on the gauges seem to be working properly except for the MPH is off by roughly 10 MPH I am wondering if anybody Knows of a trick on how to get the speedo reading correctly again, when the car is turned off the needle points to where it should but at 70 MPH I am actually going roughly 62 MPH I am getting tired of guessing My speed so any help would be Great Thanks....

and PS: Just for anyone interested I have 2 BOSS rear wings that I am selling for a 94-98 Mustang if anybody is interested either reply to this ad or contact me Via Private message

Mine did the same thing. The bast I can say is start your car up and with it running and in park then push the little needle onto the spot. After a few tries you should be able to get it.
Also I need a new spoiler. Whcih one is the Boss?

here is a picture of the Boss wing, This is not an actual picture of My wing I got this pic off the net, the wings I have are in Grey primer I do not have a picture of My actual wing but it is exactly like this one

here is how to fix your problem
take the gauge face plate off them put the needles on plug in the harness thyem turn the key to the on position but don`t start the car.now take the sppedo needle off and put it back on while the key is still turned this should fix the problem