Monte Carlo 2001 ss 3.8 temperature gauge
 

While I'm stopped the gauge rises to 230 or higher, also while driving it rises to about the same. When we turn the heat on it goes back down, could this be the thermostat???

When was the last time you had the cooling system serviced?
 

When was the last time you had the cooling system serviced?
If there is air in the cooling system it can overheat also.
Radiator & cooling system flush?
New thermostat?
Hoses good?
After all of the above if it is still giving a problem you may need new intake manifold gaskets. They seem to be a cause for overheating.

Does your fans come on?