1,900 RPM rattle diagnosis help

[armos]

The catalyst parts will end up inside the muffler eventually, where they will rattle forever. If you're planning to replace the whole exhaust anyway this might not matter though.

 

[NMBurb02]

Originally Posted By: armos
The catalyst parts will end up inside the muffler eventually, where they will rattle forever. If you're planning to replace the whole exhaust anyway this might not matter though.

There is a resonator after the cat and before the Y pipe splitting to dual mufflers, so it would probably stop at the resonator, which needs to be replaced as well. However, for the resonator to be replaced, the old one needs to be cut out and a new one welded in, but I would probably just opt for a full cat-back system.

 

[Vikas]

How could he not get a check engine light if the converter is so shot? The logic is extremely picky; even a little bit off the efficiency and the P0420 is thrown.

 

[artificialist]

Originally Posted By: Vikas
How could he not get a check engine light if the converter is so shot? The logic is extremely picky; even a little bit off the efficiency and the P0420 is thrown.

Sometimes the code doesn't appear if the O2 sensors are performing poorly, but not poorly enough to trigger an oxygen sensor code.

I once worked with a guy who had no cats on his Mustang, and left the stock sensors and programming in place. He never got a single error code of any kind.

 

[Amandacap]

Hi - did you ever figure out this issue? My 2006 Pontiac Grand Prix GT is having the same issue.