Maytag dryer drying slowly

My dryer isn’t drying like it should. I have to run it 3 or 4 times to get my clothes to dry. The lint trap is clean and I pulled the dryer apart and cleaned all of the lint out so I don’t think it is an airflow problem but I’m not sure if it’s a thermostat problem or the heating element. Can it partially burn out? Any help would be appreciated. Thanks.