My 1998 expedition overheated yesterday (gauges did not indicate hot). It smoked and when it cooled down I put coolant in and today when I went to drive it was not wanting to accelerate and the rpm dial would not go up past 2 (if that)

look for bubbles in the radiator while the car is warming up (be careful of hot coolant spitting out of the cap) if there or little bubbles it could be a good indication of a blown head gasket or cracked head

It is common to see white exhaust smoke when first starting a car, especially on cooler days. This is generally steam caused by condensation. As the engine warms up and the condensation dissipates the white exhaust smoke (steam) is no longer seen. If excessive white exhaust smoke is present well after the engine warms up, it is necessary to have the car inspected for possible internal coolant leaks. Indicators of an internal coolant leak include billowing white exhaust smoke accompanied by a sweet odor or a low coolant reservoir level. An internal coolant leak can also contaminate the engine oil giving it a frothy, milky appearance. Even small amounts of coolant entering the combustion chamber will produce white exhaust smoke. One of the main causes of white exhaust smoke and coolant loss is a cracked or warped cylinder head, a cracked engine block, or head gasket failure caused by overheating. A cracked head may allow coolant to leak into one or more cylinders or into the combustion chamber of the engine. Dirty coolant, a poorly maintained cooling system, a low coolant level, or a non-functioning cooling fan can cause engine overheating. In addition, engine wear can eventually cause the gaskets to lose their capacity to seal properly allowing internal coolant loss. Intake manifold gasket and head gasket failures are two of the most common sources of internal coolant loss caused by engine wear.
Never remove the radiator cap or coolant reservoir cap while the engine is hot or running as it can cause serious injury; always allow the car to cool down completely first. Checking for a low coolant level in the reservoir is the first step in determining if coolant loss is causing the white exhaust smoke. If the coolant reservoir is at the proper level but excessive white exhaust smoke is present, a cooling system pressure check is required to determine where, if any, coolant leaks are located. THESE LEAKS WILL CAUSE SEVERE ENGINE DAMAGE! Have the car inspected immediately.

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Internal coolant leaks can and will cause

I would trust the smoke and noise from the engine rather than a faulty temp gauge. have you checked the coolant level in the radiator and not the reservoir. The temp gauge will not give you any indication of overheating if there is no coolant to make it work

You really won't know until you take the intake off.
There could be other problems that caused the leak before the intake cracked.
Until the intake is replaced you won't be able to do a pressure test of the cooling system.
Make sure the thermostat is replaced since it could have been damaged from the overheating episode.

Let it run for about 10-15 minutes after it cools down. After the 10-15 minutes (but don't let it overheat) squeeze the top hose to see it it's hard. If it is, it's probably the thermostat, and the coolant isn't flowing through the engine to the radiator. It's just staying in the engine and getting hot.

To verify if cooling system damage exists.
Drain the engine coolant.
Remove the intake manifold.
Remove the plastic heater core feed pipe.(located under the intake manifold).
If the coolant pipe cannot be removed after removing securing hardware, the VANOS banjo bolt must also be removed thus allowing additional clearance needed to remove the pipe.
Visually inspect the front (inside) of the coolant pipe.
If the plastic on the inside of the coolant pipe shows no signs of deterioration (smooth surface) the engine should be reassembled using new gaskets and O rings where necessary.
If the plastic on the inside of the coolant pipe shows signs of deteriorated (worn away, bubbling, ect) this is an indication that the engine has been severely overheated and these components must be replaced.....Cylinder head gasket,all coolant hoses,all plastic coolant pipes,coolant expansion tank and cap, radiator, water pump, thermostat, oil and filter....

Hope this is some help to you ??

if its losing fluid the head is cracked from overheating.

You need to get coolant level checked first thing, and topped up as necessary to start with, then have to see what goes on with the temperature from there. Don't let it get all the way over to hot again, if you can help it. That can be costly. If at all possible, pull over & shut it off, but I suggest having that looked at before you go anywhere.

its most likly the termostat