Speedometer and techometer aren't working after I put fuel injector cleaner in my 95 chevy c1500 5speed?

What is your question?

After I drive it for about an hour and a half my speedometer will bounce almost up to the speed I'm traveling and my techometer will work when my foot is off the gas, when I put my foot on the gas the speedometer got right back to 0 and the techometer stops. Trying to fix this so I can get it inspected.. please help