My ge gas oven does not heat,waited 3 minutes.igniter does glow right away.Oh,the stoves burners all work,this appliance is 7 yrs old

Here is a manual about the gas ignition: https://dl.dropboxusercontent.com/u/8010163/GLO-BAR%20IGNITION.pdf
https://dl.dropboxusercontent.com/u/8010163/Electrical%20Theory%20and%20Diagnosis%20of%20Major %20Appliances%20Service%20Manual.pdf
https://dl.dropboxusercontent.com/u/8010163/Electronics%20and%20Electrical%20Troubleshooting%2 0and%20Repair%20Handbook.pdf
You will need a good digital meter to diagnose the problem. Look for one that will test millivolts so you can test thermocouples if you find you will need to test one.