I went to You Tub, typed in the situation: Dryer not staying hot.
Next, I watched approx. 5 videos. Here's a point to think about, not all videos share the same information. The basic ideas are there, but understanding of the component's function was missing in several videos. It is important to think critically about how the dryer's mechanisms operate and how they contribute to the dryers cycles. My experience with thermostats in auto and house lead to me understanding the dryer has a thermostat in the exhaust portal. IT HAS A TEMPERATURE RANGE, same as in a car, telling the igniter when to lite. If the part is worn out, then it does not have ability to detect temperature variation, and stays "Off." This is not good!
Instead of getting too cheap, I simply replaced the thermostat and coil kit-Appliance Parts Pro delivered the parts within 24 hrs. Great place to do business!!! Staff really understands and has access to information mechanically.