How to bypass the two corroding grounding issues in the back of your 5.3 liter engine. See Part 2 for the passenger side. Easy peasy solution to the dreaded "Reduced Engine Power" issue on these. Do this first before you replace the throttle body and gas pedal sensor and the wire bundle connector at the throttle body. P1221 p1515 p1120 p1220 p0220 p1515 p2135
Also the bolt size for the new ground is M10-1.5x12
Follow up video... https://www.youtube.com/watch?v=kPq1FjZndRI&t=87s