No Heat From Vents Just Cool Air...help!!!!

I have a 1995 Chevrolet Z71 and my heater just will not blow hot. I have changed the thermostat and flushed the radiatior, but still the same problem. The air has gotten a little warmer, but nothing like it was before. I have ran it for an hour and the temp guage just stays on 100. In the manual it says that it should be somewhere around 260. Any help or suggestions would be greatly appreciated.

You might have a faulty temperature gauge. Does it get any warmer after driving it for a while?

It gets a little warmer, but not as warm as it has been before. I get like hot air bursts and then it goes back to luke warm. It is nothing like it used to be. I changed the thermostat and flushed the radiator, but nothing has changed. What would the next step be?

There might be something wrong with the heater core or could be anything in the heater case under the dash. It sounds to me that it just isn't turning on. Mine went out about 2 years ago but I live in texas where it doesn't get cold enough to really need it. I wish I could be more help.

Some trucks have a vacum valve on the heater hose under the hood just before the heater core, make sure thats working right if your truck has one. And your temp sounds a little bit high I think it should be around 190, thats your coolent temp. I don't think your motor would last long at 260.