2002 Tahoe check engine light

[EricTheCarGuy]

I’m not sure how it got out of ‘adjustment’ but the computer uses that signal for timing both fuel and ignition as well as some other controls so if it’s off EVERYTHING is off. One possibility is slack in the timing chain which happens over time but it could also just be a ‘computer glitch’ that brought it out of spec, I honestly don’t know for sure but thanks for keeping us up to date as these things to into the database for others to use if they run into the same or a similar problem.