I have a 2006 with 190K that is all stock, as far as I know, but I suspect it had some mods on it before I bought it, going by the 5" exhaust and AFE air filter, but I have no real proof.
When cold I get a lot of popping through the exhaust and you can hear popping from under the hood also, when cold. Makes it sound like a single cylinder lawn mower idling with a bad muffler. It quiets down when warm and if warm enough (after driving on a hot day) it sometimes goes away.
From searching here I get the impression that I need to check valve lash and clean injectors, but want to know if anyone has advice on how to proceed with this?

Thanks,
Chris