Complex sentence: On the final day of time trials, Guthrie was loaned a back-up car owned by A. J. Foyt, and she quickly reached a suitable speed, however, she did not make an attempt to qualify.
Split into simpler sentences: On the final day of time trials, Guthrie was loaned a back-up car owned by A. J. Foyt. She quickly reached a suitable speed; however, she did not make an attempt to qualify.