I have a 1988 Nissan Pathfinder 4x4. The gas gauge and the temperature gauge would stop working at the same time when the car warmed up. They both would come back on periodically and then off again. Currently they have not come back on in about 3 months. How do I fix this problem?

Here's what I would first try, since it's the easiest. Remove and clean Engine Coolant Temperature (ECT) Sending Unit connector. If this solves the problem, you know it's standard corrosion; if not, it may mean tearing into and replacing the whole gauge assembly. If this is successful, do the same thing for the Fuel Gauge Sending Unit connector.