My whirlpool dryer element cycles too much and it takes a long time to dry clothes. The vent is clean, even ran the dryer with no vent hose and dryer was also cleaned inside and lint filter was clean. I noticed the element would come on for about 20 seconds and heat up to about 300 degrees F and then the element would shut off, dryer was still running, though. The dryer does have multiple heat settings on the knob. Any ideas what might be malfunctioning? My friend suggested that maybe the timer was stuck on a low temp setting and I might want to replace it. ??