2001 Chevy Silverado 2500HD 6.0L

Hi there. I asked earlier if I should buy this truck. I ended up buying it. It’s been great except we noticed that some o2 sensors and a knock sensor on bank 1 showed up. It idled bad but only on the first start up. When I would go backwards to pull out or come to a stop at a stop light until my car reached operating temperature it would idle from 650 to 200 just burping up and down. I called our mechanic and he recommended to just change that one sensor. We changed that one sensor and ended up with a few extra codes. (See the codes that showed up after. The codes are for both banks of the engine.)

P0157
P0327
P0332

My mechanic said that he should’ve checked the wiring harness and that he didn’t so he offered to install it for free. I purchased the harness for the two knock sensors off amazon. My mechanic advised me that so long as the plastic was decent quality the wires are just wires and wouldn’t matter. When he took the connector off the bank 2 knock sensor it shattered and was brittle and the knock sensor was cracked on the top so we put in another AutoZone knock sensor for 60 bucks. 

aftee this we went to start the truck. It goes up to 2 thousand rpms and then it drastically powers down and dies. If he unplugs the MAF sensor connector and holds the gas down and lets go. The engine idles its self at 2 thousand and doesn’t die. The second he connects it again the car drops off and dies instantly. He pulled out the throttle position sensor I think it was and he tested to make sure it was working and cleaned it with a paper towel and it still didn’t work. 

here’s the Amazon link to the wiring  my car is a 2000 Chevy but it’s a late model in the year so I use parts from the 2001 like my oil filter and stuff  is it maybe the wrong part and it’s making the knock sensors be haywire?

https://www.amazon.com/Suburban-Silverado-Avalanche-Cadillac-Vehicles/dp/B07Q2KFRQS/ref=asc_df_B07Q2KFRQS/?tag=hyprod-20&linkCode=df0&hvadid=693383443141&hvpos=&hvnetw=g&hvrand=9041743972279707639&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9033468&hvtargid=pla-738507879050&psc=1&mcid=77aeef49d9403b2db3fc0012639be92b&gad_source=1

He had me restart the battery in case of the ECM. That didn’t seem to fix anything. Any suggestions or ways to help? I’ll post a YouTube video of me trying tomorrow. Thank you!