Unplug the unit and disconnect it from the vent system.
Now try a run.
If it now dries OK odds are the vent system needs checking/cleaning.
Be sure to check that the louvers on the outside of the house open correctly.

If you do not want any lint in the house.
Take a pair of pantyhose.
Put one leg into the other and then attach this to the dryer's vent.
Leave enough room so the pantyhose can balloon out like a windsock.

Both the above will let you check the temperature and the air flow.

Note: The above is not recommended for gas dryers due to carbon monoxide concerns.

SM6199,
Try the suggestion by Denman. As a retired fireman I have seen all to many house fires because of clogged vent systems. Keep in mind the following: a dryer works on the principal of removing moisture from the clothing. It does so in the following manner. The dryer heats the contents to a temperature at or above 212 degrees F, which is the temp required to convert water to steam. When the water vaporizes it has to be evacuated from the dryer. This is accomplished by the dryer vent system. It circulates air past the heating element over the clothes and out thru the slinky hose and the vent ducting in the house. This can be thru the wall in the garage or thru the attic if the wash room is in the middle of the home. Unfortunately lint collects in the ducting and exhaust vent preventing the (steam) from escaping. Thus the clothes cannot dry completely in one cycle. I believe approximately 18 cubic feet of air per minute must move to dry clothes efficiently. So if the duct work exiting your house is clogged either interior or at the vent louver on the roof or sidewall your clothes will not dry in one or two cycles. (Supplementary info: This issue will cause the dryer to overheat and either burn out the thermostats/thermal fuses and or heating element, or overheat and possibly cause a fire). The bottom line is have your entire vent system inside and out cleaned!