Review on MOSTPLUS Oxygen Sensor O2 4pcs Upstream + Downstream Sensors Compatible with Cadillac Escalade Chevrolet Avalanche Silverado Tahoe GMC Yukon Sierra 213-4229 12609457 by Rosalio Zavala

I was doing some engine service on my truck and decided to replace my O2 sensors as I've driven 150,000 miles without a trouble code. Installed both upstream and downstream and received an engine check warning within 300 miles. Studied the code and the downstream O2 sensors were out of resistance. I have tested original OEM O2 sensors that have never been checked and compared to new both new ones showed much higher resistance. Reinstalled the original downstream O2s and the check engine lights no longer came on. So now I have 2 new intake O2 sensors and 2 old OEM's with 150k miles on them.