94 T&C Fuel Gauge Problem

I just picked up a 1994 Chrysler Town & Country with only 58,000 miles on it. It has the lcd gauges or whatever it's called. I drove it today to get new tires put on and when I left, I noticed the gas gauge read full. I drove about 10 miles and saw that the gas gauge symbol was flashing and there were no bars left on the fuel gauge so in other words it was empty. I went to the nearest gas station and threw in $5 to see what would happen. The gauge went back up to full and didn't move for another 10-15 miles so something is definately not right. Anyone have any idea what's causing this?

Bad sending unit in the tank or instrument cluster.