94 4.6 speedometer not working

my 94 4.6's speedometer doesn't work, it will jump up to about 30 when driving and just stay there. I took the dash apart and cleaned the electrical connections, but it still does it. I've heard there is a speed sensor somewhere which might be to blame. Any advice would be appreciated. Also, the gas guage doesn't work either.

Sound like to me that the speedometer is bad, not the speed sensor. I had almost the same problem. I went to my local junk yard and pull use speedometer, and change with no problem it did not need update the computer.