If you own a 2007 or newer diesel truck, then chances are it's equipped with a Diesel Particulate Filter. Mandated for use in modern diesel vehicles to reduce particulate emissions, DPFs have earned the scorn of performance enthusiasts and ordinary truck owners alike for various reasons. Some have even gone as far as completely removing the DPF system from their vehicles.
DPF deletions are a popular alternative to maintaining troublesome DPF systems.
An important inspection your vehicle will have to undergo is a smog test. It's designed to ensure your vehicle's emissions are safe and thus won't lead to air pollution. To pass these tests without any problems arising, you'll want to take these measures.
Inspect the Check-Engine Light
If your check-engine light is on, you won't get very far in the smog testing process. In fact, if this light is on or turns on when you have your vehicle inspected, it will automatically fail no matter how good of condition it's in.
If your vehicle idles too high, or too low, the idle air control valve may need cleaning. An idle air control valve regulates the amount of air that gets into the engine. Sometimes, it can get clogged with carbon, which makes it stick. Regular cleaning can keep the idle control valve functioning properly. Follow this guide on how to clean your idle air control valve.
Prepare to Clean the Valve