what's up guys..
when i started my ranger.. (it's a 2001 4.0l BTW) the speedometer, rpm gauge all went crazy...the gauges won't read and just seem to float around.
i took it to a place Galpin Ford recommended me to and it worked for about 5 minutes then stopped reading again!
Mine did that when the battery was going dead, the needles would bounce all over the place and read wrong. couple of days later and it started clicking when i tried to start it, replaced the battery and everything was back to normal.
I also had this exact same thing happen to me but it was in a Mustang, not my Ranger. It was under a certified used car warranty and I didn't even have to pop the hood. The service writer at the dealership said "you replaced the battery cable end didn't you?" I had just replaced one of the cables with a $1 Advance taiwan junk end. They went ahead and replaced the cable with a Factory ford one under warranty and that was 10 years ago. I still have that car and the gauges have never had an issue again.