98 Grand Marquis rattle in exhaust system

External Since: Oct 19, 2004 Posts: 146

mstrspy wrote:
> It sure seems suspicious that I get a rattle in the exhaust system
> when the engine is running and I get the code "insufficient catalyst".
> Is there an O2 sensor tht could be broken and flapping in the breeze?.
> This car has 2 cats and I hoping that I don't need t replace both.
> By the way, the engine runs great and gets good fuel economy,
> insufficinet catalyst or not.
> M

One of your catalysts has broken apart internally and the parts are rattling around
inside. Smack each converter with a rubber mallet, you'll find out which one it is
pretty quick. The fault code definition will tell you also. Bank 1 is the right side,
bank 2 is the left side.

External Since: Oct 19, 2004 Posts: 146

mstrspy wrote:
> It sure seems suspicious that I get a rattle in the exhaust system
> when the engine is running and I get the code "insufficient catalyst".
> Is there an O2 sensor tht could be broken and flapping in the breeze?.
> This car has 2 cats and I hoping that I don't need t replace both.
> By the way, the engine runs great and gets good fuel economy,
> insufficinet catalyst or not.
> M

One of your catalysts has broken apart internally and the parts are rattling around
inside. Smack each converter with a rubber mallet, you'll find out which one it is
pretty quick. The fault code definition will tell you also. Bank 1 is the right side,
bank 2 is the left side.