Car warms up normal with temperature gauge regular position and heater works. Once, I get on the road the temperature gauge goes up and the heater stops blowing heat( blows cold air). After about a minute or so, the temperature guage returns to normal position and it starts to blow warm air. This happens on and off while i am driving. What seems to be the problem?

1. Engine Coolant Temperature.
If the thermostat in the cooling system is getting stuck in the open or partially open position rather than opening and closing as needed to keep the coolant at the required operating temperature then you will get the results you have described here with the coolant temp dropping as you drive. The radiator is providing optimum cooling when the car is moving and there is plenty of cold air flow through it.
I am assuming the temp gauge in the vehicle is reading correctly.

Thermostats in the cooling system do become faulty in time and it may well never have been changed (or only changed once) since the car was built and is possibly gummed up with debris. With those symptoms I would definitely change the thermostat. Make sure a full flush of the cooling system is done at the same time and refilled with fresh coolant.

2. In Car Heater.
I would not worry about the interior heating until you change the thermostat on the cooling system. However if you continue to get cold air from the heater then there will be an issue with hot coolant from the cooling system being restricted in flowing through the heater core.

This could be one of a few options.#1 could be as little as 1 quart to one half gallon low on coolant in radiator; #2 could be thermostat may be stuck in Open position all the time ( check temp gauge to see if engine is at Normal operating temperature ) #3 could also be stopped up Heater Core....Check this by simply touching heater hose going into heater core and heater hose exiting heater core, at any rate if the core isn't stopped up, Both hoses Should be warm or hot at regular operating temperature of engine warmed up.

That is pretty much normal, the heater blower fan acts like the radiator does and helps cool the water passing through it by extracting the heat from it. then once the car inside temp warms up it goes back to normal. Nothing to worry about.

The blend door may be malfunctioning if the heater core gets hot enough to heat at any given time.

Computer might need reset.

Yes,it's probably the blower motor resistor it should be on the passenger side under dash on the heater box, probably mounted with two screws and has plug in connection, as far as the temperature guage I would check to be sure that the radiator fans are coming on when the temperature that controls them is reached, also check fuses.

Hi Code P 0217 does point to the thermostat but it also points to the wiring, cooling system, and the temperature sensor, to check the thermostat start engine then once the temperature gauge in the car reaches normal the thermostat should open and the top hose that goes into the radiator will warm up quickly as the thermostat opens, if the thermostat is stuck in it's open position the top hose will start warming up before the engine reaches it's working temperature, hopefully i have explained it clearly,

the temp sensor sounds like it maybe bad and not responding the way it should.they are cheap 10 - 20 dollars and easy to replace.

sounds like you need to replace the thermostat.

open thermostat or instrument voltage stabilizer.