Maytag Dryer Takes to long to dry

My dryer takes a long time to dry a load of clothes. Lint trap is clean and vent duct is clean as well. Took it all apart to check it. All thermostats check out when checked with a multi- meter. Also checked fan where it connects to blower motor and it is not stripped out. Have 220 running to dryer. Is it possible I have a thermostat not cycling properly? There are two on the exhaust side and 1 on the heating element. Which one do you think it would be? Any help is appreciated. Thanks!!