Temperature gauge reading hot on 96 Honda Passport ???

I have a 96 honda passport with a 3.2L V6. The temperature gauge maxes out at the hottest point just after about a minute of running. This is after sitting over night. I have replaced the waterpump, timing belt, thermostat, flushed the radiator, and replaced the coolant. Yesterday I took the thermostat out and ran the engine and still the gauge maxes out after about a minute or two. The darn temperature sensor is between the engine and the firewall and very had to get to. Does anyone know what the problem could be? Air pockets, bad sensor, bad ground ???