94 Gt Running Extremely Cold

As Hissin said, the stock gauge is unreliable but I can give you my experience with the stock gauge on an engine that's in good condition. I've owned a 94 GT, a 95 GT and a 94 Cobra Clone, and the stock gauge on all three has acted in basically the same way. Hopefully this general description will help you figure out if your car is acting "normal".

The average operating temperature while driving should have the needle somewhere around the "N" or "O" of the word "NORMAL" behind the gauge. Exactly where depends on what temperature thermostat you have, the type and condition of your radiator and the accuracy of the stock gauge. The low-speed fan should kick on when the needle is somewhere around the "M" in "NORMAL", and the fan should stay on until the gauge drops to somewhere in the "R" range.

When you start the car and the engine is cold, the gauge will slowly rise from the left edge until the thermostat opens. At this point, the needle should be somewhere around the "N" or "O" in "NORMAL". Once the thermostat opens, the temperature will drop somewhat but will rise back up again. The thermostat will then open and close as needed to keep the engine at a minimum temperature. So if it's cold out it's possible the temperature may never get very high.

If I'm driving under 35mph, and usually stuck in traffic, the temperature gauge will slowly rise until the fan kicks in. If I'm driving 40mph or faster, the temperature will never rise over the "O" in "NORMAL". The temp will rise a bit after exiting the freeway, especially if it was a long drive, but it won't ever reach halfway unless I run into traffic like I mentioned above.