My Toyota Tacoma had an 02 sensor problem, or so I thought. Autozone had read the codes coming from the truck and said that was the problem. After replacing both sensors, I still had the problem. Hardin Brothers Automotive Technicians troubleshot the problem and came up with a faulty Mass Air FLow Sensor, replaced it, and I haven't had any problems since. In fact, The truck runs better than it ever has and gets better gas mileage. Thank you Hardin Brothers Automotive.