Thank you for your question and I understand your concern. The burner is supposed to cycle off and on in order to maintain an average operating temperature of approximately 150 degrees when set on high heat. Remove the vent hose from the back of the dryer and start an empty dryer and monitor the exhaust temperature with a thermometer. The exhaust temperature should average around 150 degrees if the dryer is operating normally.
Now, if you have a restricted venting system it will cause the flame to short cycle/shut off before it reaches operating temperature. If you find it doing this with the vent hose connected, check and clean the venting system of any kinks or lint.
If you find the glow bar igniter glowing red and then fading off without any burner ignition, then this would indicate weak solenoid coils mounted on top of the gas valve assembly and both coils will need to be removed and replaced. You can watch the burner operation by prying off the small square plastic inspection cover located below the door. Start the dryer and monitor the glow bar operation. The burner should ignite each time you see the glow bar igniter glowing red.
Reply with additional details of your finding for further information.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services