I have a air/fuel ration imbalance code (p219b), what could be done?

Hello, can't even begin to troubleshoot this code until you restore the exhaust to factory condition. And, when you do, I'm going to bet it solves the problem. You see, engine performance management depends on certain factors, such as the presence of various components. For example, if you don't have catalytic converters, how do you expect to have "pre" and "post" converter measurements for the engine's processor to navigate? Breaking the law isn't the answer. I know you are probably going for performance and sound upgrades, but you'll need to do that legally and properly. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops