My cluster sticks. It will move in 5 mph increments and then stick there until our speed drops about 15 mph. So does the rpm gauge. Is this a bad cluster?
I would say yes. Resistance in the circuit would not make it increase in 5 mph increments.
You can do a "bulb test" by holding the trip counter reset button while starting the vehicle and see if the gauges sweep properly.
Other than that I would say this is a case where you would replace the suspected component with "a known good one" and take it from there.
When you were swapping out the clusters on these type of cars and you have to take out the entire thing, you are going to have to get the safety disabled or be able to get the new cluster married to the car it is going into or the anti-theft will not allow the car to start