my dryer gets warm and takes about 2-3 times longer to dry a load . I have cleaned out the vent and shortened the vent pipe so is only about 32" long. clothes eventually get dry but takes a long time. It does not seem to be fully heating. what should the temp be coming out of the vent? what could be causing this and how would I check the probable causing. I have no meter and do not know how to use one. thank you.