Swelter by D. Jackson Leigh

After her affair with a married senator makes prime time news, congressional aide Teal Giovanni is fleeing her shattered life. Betrayed by the lover who was her partner in a successful law practice, August Reese is waiting at a small cattle ranch to testify against a drug kingpin. Attraction sparks when Teal's aging Honda blows its engine and she and Griffin meet on a steamy Texas blacktop. But as the spark bursts into flame, their worst nightmare comes calling. Will they survive or swelter as the heat becomes unbearable?