Background: 04 Silverado with 5.3L, approximately 79k miles. CEL came on roughly a month ago, motor chugging however vehicle did not stall. Had plugs & wires changed as well as fuel filter service completed. All was well for a month then same symptoms came back, CEL came on and stayed on; when accelerating the light blinks. Had codes read at Autozone, told me o2 sensor getting bad oxygen and the engine was misfiring. Took back to shop yesterday (who originally did the repairs), reset the code and vehicle seemed to be fine however on the way home today same issues again.

Any thoughts on this? From the outset I felt an oxygen sensor was the culprit however I've been told otherwise by the shop. Thanks!

 

the cel will blink when underload and an issue is present that will damage the cat. therefore i would address this soon.

sounds like its misfiring underload. I've seen this happen from clogged cats (hammer fist the cat; does it rattle) and bad o2 and fueling issues.

You need to post the codes and some live data from the front 02, maf and fuel trim to accuratly diagnose this.

 

Might this be a weather related issue? When I picked it up last night it was dry; today has been wet/raining all day. Looking back, these issues have been most apparent when wet.