I've been driving my 89 Chevy S=10 Blazer without knowing they need an oxygen sensor every couple thousand miles. Ah, well.
4.3 engine. I finally found the sensor on the passenger side of the engine, between spark plugs 2 and 4. Truck was bought about 120,000 miles and presently has 265,000 miles. Might be time for a replacement sensor.Question: Is it better to change the sensor on a cold engine, or on a hot engine? And any practical tips from someone has done one?