New Temp and Fuel Gauge Problem

i finally got the new dash and engine harness installed in my car. The car started up fine and the modulation that I was having at the ammeter and in the electrics in the car are gone. But I have another problem that has me at a loss. I replaced the fuel and temp gauges that were both burned up and I put a new solid state IVR in the dash. However when I turn the car on, the needles on the two gauges are constantly bouncing. But there is no bounce in the ammeter. I also replaced all of the nuts on the back of the cluster with real nuts, not those push in style, and I added an extra ground wire to the underdash from the two circuit boards. Any ideas what might cause the two gauges to bounce even with all the new stuff? Might order a traditional style IVR to install and see if that makes any difference.