2011 Chevrolet Impala fuel system problems

When I left my house to run to the store the gas gauge was reading half a tank. The store I ran to was 6 miles up the road, when I started the car and was coming home I noticed the gas gauge was below a quarter of a tank. By the time I got back home (6 miles away) the gauge was reading between half and a quarter tank. I also had a 2007 silverado that did the same thing, not sure but maybe chevrolet needs to seed a recall out for the fuel gauge sending units.

The check engine light came on (and had gone out) previously. Dash said "service stabilitrac, engine power reduced" and a mechanic said it was a "sensor in the gas pedal" and that if it kept happening we should replace it. I didn't fully realize that this meant that the throttle would disable itself while I was driving in morning rush hour traffic on the highway in the left hand lane going up a hill doing 60 MPH.