Firstly I've used Bosch for a couple of decades on many makes and models and never had an issue, so the reviews were not that important to me for this purchase. The order was received quickly, the price was very competitive so I went to work swapping them out on my just tuned up (plugs, wires, coils, filters) 2011 Silverado 2500HD 6.0 truck which was running way better after the tune up, so the O2s were just to be the cherry on top of getting the most out of my 6.0. Got them in, and all seemed fine until about a 1/4-1/2 mile down the road when all I can assume the circuit went open loop and started looking at the O2s to help with the fuels air mixture and all hell broke loose. Kicking and bucking, popping in the exhaust, "Service Stabilitrak and Traction Control" errors and lights, then the CEL came on and it was all I could do to limp it back home. Next day I took it all apart again to make sure all was well, and nothing was off. So that's where the research kicked in as in my mind it still can't be the Bosch O2 sensors. Went to Bosch's site to make sure these were indeed the correct ones for the truck to make sur the Amazon "This fits your vehicle" piece was in check, and this is the part number from Bosch's site for my truck so that was out. Looked some more and found several reviews of similar issues on this item on Amazon alone from PGR in 2018, Adam Blaszyk in April 2021, Kellywaw 4/2019 & (one of my favorites) Monk E. Rench from 11/2017 all with similar immediate issues. Looked further online and found several more reports of these sensors doing all kinds of erratic things. Still not convinced I bought a scan tool that could show live data, and that clenched it. Both sensors read a pegged voltage and never fluctuated one bit open or closed loop, so that sealed it for me. Finally tracked down some Denso ones at a local parts house, got them and put them in and immediately the truck came alive again and the DTC codes reset and the live data showed constant reading fluctuations as you expect. Very disheartening to have such a trusted brand for decades fail so spectacularly in this particular application anyway. Will be trying to return to Amazon as failed products, but I'd advise anyone considering these to thing very hard about it and be very ready to source an alternate if you have similar issues as myself and others on Amazon and other locations alike.
