This is my first time to ask a question so here goes. I have an '89 Mark VII with 63,000 original miles. It now takes about 10 minutes of driving before the speedometer starts to read. During the 10 minute perion, the fuel gage also "floats" around (within a few gallons of what is actually in the tank. ONCE THE SPEEDOMETER STARTS WORKING, all is well for the rest of the day. Any ideas of what the problem is and how to fix it? Thanks for all input.