I have this problem in a 1994 Prelude (94 and up have the EL lighted gauges). The speedo will be accurate, then BAMMO I'm going 140mph or 0mph. In my car, it appears to be heat sensitive. On a hot day with the car in the sun, the speedo goes wacky and the EL lighting and the odometer goes blank and quits working. I replaced the VSS twice. No fix. I removed the cluster and replaced a capacitor or 2. No fix. I removed the cluster and pinched every single connector pin (take apart all green connectors 1 by 1) and still no fix. My car has 111,020 miles on it. I got a used gauge cluster from a junkyard for $80 with 188,140 miles on it and it works fine. I had to get a different gauge. Now it works.