Oh I did, and they were fantastic suggestions. I guess I should give a more thorough update...
The truck was due for emissions testing in August. It couldn't pass with the knock sensor. So I went elbow deep and tore the entire harness and ECU out.
Inspected every square inch and found nothing. For good measure, I cut off all the jackets and traced/replaced the knock sensor wires from the ECU to the sensor and put ANOTHER pigtail connector on for the sensor. Cut off and replaced all the ground ends and replaced all 3 battery cables.
Put it back together and got the ol' MIL middle finger.
Emissions were due in 2 weeks and I was desperately trying to survive online schooling with a kindergartener at this point. Out of time and out of patience, I took it in. They diagnosed the ECU in 20 minutes, presumably using the tech 2 (remember, last I looked I remember them being quite pricey).
The guy fully expected me to do the job myself. I don't trust shops. Every shop I've been to in 22 years of owning cars has screwed me. Usually either break more than they fix or charge me for repairs that don't solve it, then charge me again for the right repair. This guy knows this. I have a "relationship" of sorts with him because he's the only shop my elderly mother can go to and come out in one piece... and I audit their work every time
. So he told me it was the ECU and and said I could come get it, he then told me it had to be flashed after the swap I threw up my hands and paid him to do it.
So I DID follow the advice, it just wasn't enough this time... now that I know the tech II isn't over a grand, next time I'll take a wack.
I own all GM's and that ain't changin' any time soon...