I have a whirlpool gas dryer lgq9857lwo. The

There is a flame sensor on the burner, it is probably the problem. It can get dirty(wipe the windo on it). Also with the drum out you have short circuted the air flow. Clean the inside as lint burns to well and is hazardous. The dryer may be equiped with a one time high limit switch, protection in case of over heating, it may need to be replaced. The thermo disc (thermostat-s coul be bad) Check all components with a multimeter. Ust the wireing diagram usually inside the control head, as a guide. GoodLuck. If this was helpfull, Please leave Positive Feedback. Thanks, SnugglePants