Gutting Cat

[legotech7]

I have a 95 Sonoma I would like to gut out the catalytic converter or replace the cat with a straight tube. Can any one tell me if doing so, would make my check engine light go on and if so, would it remain on after eliminating the cat?

[old_master]

The downstream oxygen sensor, (after the converter) is used by the ECM to determine catalyst efficiency. If the converter is not doing its job, or it's removed, the check engine light will come on, and stay on, until the problem is repaired. Removing a good converter will not affect engine performance. If it's restricted, yes it will affect engine performance. Keep in mind you could buy 20 converters for the cost of the fine alone for tampering with the emission system, not to mention the jail time. And yes, the EPA does enforce the law. It's very easy for them to trace back who tampered with the system, especially after you sell the vehicle. If your state requires smog testing before you can get license plates, you're in some serious trouble if the converter has been tampered with. It's your vehicle, and you can do what ever you want to it, but if you license it and drive on public roads, you're breaking the law.