Have you downloaded the emissions and driveability manual for your truck? It'll have a bunch of useful info, including where the o2 sensor is intended to be from factory depending on your model. Apparently it varies quite a bit which is surprising to me. Pay attention to the series,engine code/rpo..etc..
Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...
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