FUEL GUAGE PROBLEM

I had an interesting find yesterday. I decided to test my fuel and temp gauges using a device that allowed me to “dial in” a desired DC voltage. I adjusted it to provide close to 5 V at the gauges and tested each with the variable resister that I have. They both worked perfectly. I re-checked the voltage limiter and it is still giving the pulsing voltage - suggesting that its working somewhat as it should. My gut tells me that I should abandon the voltage limiter and come up with a device that will provide a steady 5 volts at the gauges. Does that make sense to you?
A quick search within the site here and I came up with a reference to a solid state voltage limiter by a company called Real Time Engineering. Specifically - they offer a device called an IVR4 for my car for $50. Have any good or bad experience with that source?