Change the oil and filter. Do a tuneup on it, replacing the air and fuel filters, and at least checking the plugs. Make sure the plug wires are all in good shape. I normally gap my plug 1-3 thousandths more than what's recommended in order to get a hotter spark.
You say the air coming out of the heater is nice and warm. That tells me the engine is running at proper temp, it's just the sending unit that's reading incorrectly. If the needle on the temp gauge doesn't move at all, I would suspect either a completely failed sending unit or some sort of broken connection between the power source, the unit, and the gauge.
Thursday, April 4th, 2013 AT 3:33 PM