My temp gauge reads 220 degrees when the car warms up to operating temperature. I hooked up a scan tool and the reading from the coolant temperature sensor was fluctuating between 194 and 196 while the gauge read 220. Ive replaced the sending unit twice and still i get the same result. BTW, i still have the 195 degree thermostat in my car.

Stock guages aren't very accurate. You'll have to get an aftermarket guage if you want accuracy. you could probably try another stock guage but it would be hit or miss on its accuracy.

Ditto.
Even with new senders, my factory gauges (92) are unreliable.
I've added Autometer mechanical Water Temp and Oil Pressure gauges. These are accurate with or without power, no matter what battery voltage/grounding problems, etc. you may have.
Sometimes they read the nearly the same as the factory gauges and sometimes there's a pretty large difference.
Worth the money for the peace of mind alone!
I remember freaking out the first time I saw zero oil pressure, hooked up a mechanical gauge and it was about 30 psi at idle!
Whew!
-Rich-

The temp sensor uses resistance to read the temp. Check the resistance of the sensor wire (frayed, melted etc), because if it is too high, the gauge will read high as well.

I have an aftermarket mechanical gauge giving me the same crappy reading as the factory gauge was. I was looking at the area around the sensor and Im not a hundred percent sure there is a heat shield between the sensor and the exhaust manifold.