Catalytic Converter Hi there, I have a 2006 Infiniti M45 that stalls while driving and misfires on restart. I've already replaced crank and cam sensors and an evap leak. Infiniti is asking me to replace the front 2 cats but say cats have nothing to do with the car stalling or misfiring. Catalytic converters are pretty expensive to replace. What should I do?

The PO420 code is a generic code indicating a problem with the catalytic converter system efficiency below threshold. This issue can be caused by several factors, including:

1. A clogged or failing catalytic converter
2. An exhaust leak before the catalytic converter
3. A malfunctioning oxygen sensor
4. Fuel system issues, such as a clogged fuel injector
5. Engine misfire
6. A damaged or failing ignition system
7. A vacuum leak

Here are the steps you can take to diagnose and fix the issue:

1. Check the catalytic converter: If the converter is clogged, it may need to be replaced.
2. Examine the exhaust system for leaks: Leaks before the catalytic converter can reduce its efficiency. If a leak is found, it should be repaired.
3. Replace the oxygen sensor: If the oxygen sensor is malfunctioning, it can cause the engine to run too rich or too lean, which can affect the catalytic converter.
4. Check the fuel system: Clogged fuel injectors can cause a lean fuel mixture, which can harm the catalytic converter. Have the fuel system checked and cleaned as necessary.
5. Repair any engine misfires: An engine misfire can damage the catalytic converter over time. Fix the misfire and see if the code returns.
6. Check the ignition system: A faulty ignition system can cause a misfire and damage the catalytic converter. Have the ignition system checked and repaired as needed.
7. Find and fix any vacuum leaks: Vacuum leaks can cause a lean fuel mixture and damage the catalytic converter.

It's best to have a mechanic diagnose the problem and perform the necessary repairs, as some of these repairs can be complicated and require specialized tools.

A blinken lite means the cat converter is bad. Unplug the computer n clean the pins then replug. Connections on old cars often get dirty. Get a datastream run at a privateshop to target issue.Its better then a code reader. Wiring harness should be inspected for flaws

a faulty engine coolant temperature will cause vechicle to stall out during climate changing.

Oh, but it can. If a piece of the converter flakes off inside to cause an obstruction, engine exhaust pressure will build up.

Have u checked the cadeletic converter. It can do funny things

This is starting to sound very much like a blocked catalytic converter on the exhaust system. Try unbolting the exhaust in front of the catalytic unit and see if it will start and run normally. If it does then the unit needs replacing, if not then thats me tapped out for ideas.

You didnt say what country or state you are from. If you are from the US removing the cats will cause your to fail safety and emissions inspections due to missing components ie no catalyctic converter. The cats dont have anything to do with exhaust noise. They are there to capture bad emissions. What dealer did you take it to? A reputable dealer would not have told you straight pipes would solve the problem.

The cause of this is either a defective idle speed control valve or an intake maniflod gasket leak. The Catalytic Converter has nothing to do with idle, so that was not money well spent.

it could be a clogged catalytic converter.it will cause loss of power and make the engine struggle to get up to speed...

new sensors or reconditioned ones from a scrapyard,best bet is main dealer