engine lite code catalice efficancie

[big white bufflo]

my sisters bonni 97 3800 we just put a intake on it 1 month ago it put a code up for catalitc efficancie out of range bank on put scanner on it looking at o2 sensors one seem to vary alot more than other im leaning to replace that o2 sensor i want some insite on this im new on the reading of live data on scan tool and want to know if im right i cant remeber the number on the code

[xdhd350]

Pre cat sensor should show lots of switching activity as the PCM varies the mixture from rich to lean and vice versa. The post cat sensor should show very little activity. This is normal and shows the catalyst is doing its job. What you don't want to see is NO activity on either sensor or a lot of switching on the post cat waveform.

The below efficiency code means that the PCM has determined that your car is putting out emissions at greater than 1.5X the EPA standard.

There are a variety of reasons that the catalytic converter could be loaded up. Any contaminants such as coolant, oil, or running an excessively rich mixture for extended periods can cause deterioration of the beads in the converter. It's possible that you got some contaminants in the cylinders when you replaced the intake. It doesn't take much. I had a local shop ruin a brand new cat on my car when they replaced the LIM gasket and let coolant run through the engine. They tried to deny it, but the white gunk coming out the tailpipe was the 'smoking gun' so to speak.

[big white bufflo]

ok thanks for the reply i justhad a intake go bad on this unit and it has not showed this code since so i assume it just was gumed up from the coolant and oil