Have you tried cleaning the sensor bars with some alcohol? Previous owner may have used dryer sheets, which can sometimes leave a residue on the sensor and lint filter.
I cleaned everything while I had it apart, including those sensor bars with alcohol as that was my first thought. I tested the thermistor and it checked out electronically, but that's not always a guarantee to be correct. Like I said, it ain't the end of the world. I just use timed dry 45-60 mins and all is fine.
I turned the front feet out about an inch. I ran one load of towels so far on sensor setting and they were dry. One thing I notice about this dryer...it seems the drum turns faster than my GE did...the clothes tend to stick to the drum more instead of dropping down. Still for $20 it does ok. It has good airflow outside. On a cold day I can see the steamy exhaust going way out in the yard.