My mom's Accent suuuuucks
 

She has had the transmission replaced under warranty at least three times. It is a 2002 accent. She is currently getting only 15 mpg. I'm guessing it's a faulty oxygen sensor, but I'm not sure. Does anyone know of a good Hyundai mechanic in the Salt Lake City area? She is 70 and lives in Sandy, and my dad is in a nursing home and can't help out.

Hi and welcome to the forums.
Best thing for you to do is to go to your AutoZone in that area and they can tell you who is good, cheap and can help you from their customers..

WheelBroker1 :)