If you have a hard time passing emissions. Here are a few things may make it easier. Also a way for heavily modified Sy/Ty's to pass without many problems.
- If Cat is plugged, replace it.
- Turn fuel pressure all the way down. The truck should barely be running, with 0 psi.
- Make sure the engine is really hot before the test, the cat works best like this.
- Try and keep the idle at 1100-1200 RPM, if you can sit in it and keep it up.
- With all of these everyone should be able to pass.