Chevrolet Camaro Questions

1999 Chevrolet Camaro. It go's into limp mode when engine light DTC P1515 comes on. The gas pedal stops working and it tries to kill me. It does it on the highway, it's intermittent and dealer can't fix, unless it's doing it when they have it. Sometimes P1516 comes up. You have to pull over and turn off so it can reset. Its been 5 years.