If you remove the cat converter from a 1995 Dodge Ram 1500 with 5.9 liter engine and place 02 sensor in new pipe will it run ok or do have to something computer?

Removing the catalytic converter from your 1995 Dodge Ram 1500 and simply placing the O2 sensor in a new pipe will likely cause problems. While it might run, it will probably run poorly and trigger numerous check engine lights. Here's why:

* Emissions: The catalytic converter is a crucial part of the emissions system. Removing it will result in significantly higher emissions, potentially leading to fines in areas with vehicle emissions testing.

* Oxygen Sensor Readings: The O2 sensor's job is to measure the amount of oxygen in the exhaust to help the engine's computer (Powertrain Control Module or PCM) adjust the air/fuel mixture for optimal performance and emissions. Without the catalytic converter's filtering action, the O2 sensor will detect a dramatically different exhaust composition, leading to inaccurate readings. This will likely cause the PCM to run the engine in a "fail-safe" mode, resulting in poor performance (rough running, poor fuel economy, lack of power).

* Check Engine Light: The inaccurate O2 sensor readings will almost certainly trigger a check engine light. This light will stay on until the problem (missing catalytic converter) is addressed. The codes stored by the PCM will confirm the issue.

* Potential Damage: In some cases, running without a catalytic converter can cause damage to other engine components over time due to the increased exhaust temperature and different exhaust gas composition.

You don't just need to do something to the computer; you need to address the fundamental problem of the missing catalytic converter. While some aftermarket solutions exist (like high-flow cats or cat simulators), simply removing the cat is not a recommended or legal solution. Ignoring the issue could lead to further problems and potential legal consequences.

If you need to replace your catalytic converter, consider these options:

* Replacement Catalytic Converter: This is the safest and most legal option. Find a direct-fit replacement specifically designed for your 1995 Dodge Ram 1500 5.9L.

* High-Flow Catalytic Converter: These offer slightly improved exhaust flow but are still within legal emissions limits (though this varies by location and regulations). Ensure it's legal for your area.

Consult a qualified mechanic for advice on the best course of action for your vehicle and location. They can diagnose any underlying issues and recommend the appropriate repairs.