temp gauge - '90 Maxima - help

[judyg]

1990 Nissan Maxima - 6 cylinder, automatic - 250k+. I was coming home from the beach (car had been sitting for about 3 hours) and had been on the road 10 minutes @ 45-60mph when the temp gauge flew up to H and then immediately came back to its normal position. It did this at least twice. I pulled over, left the engine running and looked under the hood - all seemed ok; no leaks; no steaming; temp gauge remained in its normal position. Drove the rest of the way home (another 60 minutes at 50 mph)and nothing else happened. When the gauge flew up to H, it was like it has no resistance, as if it was broken, acting erratic, or something.

Any ideas on why this would happen?

Someone suggested an electrical short ?? I just had all the spark plugs and wires replaced in the last 2 weeks.

Thank you in advance for your help.
Judyg

[judyg]

fyi - replaced the temp gauge sensor. Problem reoccured. After much testing (engine works fine), mechanic will replace voltage regulator that runs temp gauge, odometer, fuel gauge and tach. Right track?