Can you help me with anything about 1991 Honda Civic temperature gauge problems.

My car will fluctuate on the temperature gauge from normal to running hot, and then when I pull in driveway at idle it will run normal again.

I have put in a new radiator, thermostat/gasket, and replaced temperature and water temp senser under distributor..

I have replaced all hoses and all run hot except the long bottom radiator hose that connects the radiator and the top of the engine.

I believe there is a problem related to the thermostat and housing.

Can you help me with anything

You have done a lot of good things. A Honda-trained technician told me most Hondas overheat due to an improperly installed thermostat or due to the cooling fan not working properly. Install the proper thermostat, with the pin up and the spring towards the engine. The thermostat mounting rubber goes over the thermostat.

Under the distributor are the Engine Coolant Temperature (ECT) Gauge Sending Unit, located on the left, and the Engine Coolant Temperature (ECT) Sensor, located slightly below and to the right. I would replace the ECT Gauge Sending Unit and clean the connector.

I would also check all underdash and underhood fuses with a test light or multimeter. A number of these fuses control power to the Radiator Fan Relay, located in the underhood fuse/relay box. Also, I would check the operation of the Radiator Fan Relay, Radiator Fan Motor, and the ECT Switch (located on the thermostat housing).

The links below may help:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post235973

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-7.html#post1365453

Finally, ensure you properly bled air from the system.