2009 Tahoe 5.3 189,000. Noticed a ticking under the hood for a little bit but never really thought about it. In the video attached below this was the ticking on a cold start. But when driving you can hear it when giving it a little gas. Especially idling, you can hear it outside. The AFM has been disabled. There is one engine light but it is for low cat efficiency. Just trying to figure out what ticking is.