Stipulated loop hose not circulating

You did not mention which engine you have in your 4Runner. Only one thermostat for your vehicle's engine, regardless. Your check engine light certainly isn't saying you have a "loop hose not circulating". OBDI vehicles would give you precious little information, and that code would be used to perform hands on troubleshooting. The temperature gauge should show whatever is correct for it to show. There is no "right" or wrong. For a 24 year old vehicle, your gauge could be worn or bad, wiring and circuitry suspect, engine coolant temperature sensor could be an issue, a ground could be a problem, and above all you could have a cooling system problem. Auto parts store sell auto parts. They have 'code readers' that give you a false sense of security that you're actually diagnosing something, but a technician with training and skill and tools and manuals actually does the diagnostic testing. Seek that for proper assistance.