The video of the TPS replacement was just for basic understanding of what needs to be done to replace it if need be. He didn't do it exactly right and never used any instrumentation to ensure he had it adjusted properly. If you don't check it, you'll never know. Ballpark lucky, perhaps. Without the TPS voltage being checked/adjusted properly, the ECM doesn't know if you're at WOT or not. It matters to the CCC stuff.
The TPS cap does 2 things. It's supposed to hold the adjusting screw in place and also keeps out dirt, etc. But if someone had removed it before, and never replaced it, you would have no need to drill out the cap. The book also says you can use thread lock compound GM p/n 1052624, which is the same thing as Permatex High Temperature Sleeve Retainer on the original screw without a cap.
If the adjusting screw was replaced with a service screw, they already were supposed to come with a locking compound on the threads. That's usually not ever.
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