A neighbor has a 5.0 TBI (L03) in his classic car. A few weeks ago, he
drove to Mexico. Several times, he had to fill up with high sulfur
Mexican gas. On the way back, the fuel economy had dropped 20%. I
hooked up a scan tool - the ECM had set a code 13. A short test drive
confirmed the code 13 - the O2 sensor voltage never left a range of four
AtoD converter values centered at the sensor bias voltage. This sensor
was _dead_. After putting in a new sensor, the ECM and engine were once
again happy.
Question, did the Mexican gas poison the sensor? Or might it have died
due to other causes?