Dryer runs. No flame - no heat.
Answer Hello John. You will need to test the thermostats and the flame sensor and make sure they are good. They should read closed for continuity. Also, check the igniter to see if it is good. If it is not glowing, test for power. Here is a link on how to use a multi-meter for the testing procedures. http://forum.appliancepartspros.com/oven-repair-including-ranges-cooktops/4810-how-check-continuity-ohmmeter.html
Dryer flame turn off after few minute and won't turn on until re-plug the power.
Answer Hello Danny. Based on the information you provided, it sounds like the coils may be bad and need to be replaced on the unit.