Hey All,

I have a 2000 Sentra GXE 1.6L. I get an engine code telling me the Cat is going out. What tests can I do to determine if it is the tail end or the manifold going out?

Thanks for the help.

i hope you dont have the gxe with 4 o2 sensors...

get the code cleared and see what comes back up. you have one in the header and one after the midpipe.

my guess from lookin at the FMS, is bank 1 sensor 1-2 is the one above the precat in the header, and bank 1 sensor 3-4 is the one after the cat in the header. you shouldnt get a cel for the cat under the car.

you have the 1.8l qg18de.... telling us the code is for the cat going out is vague, give us the code so we can help, as was mentioned earlier sensor 1-2 are the mixture feedback sensors, and 3-4 are the catalyst efficiency monitors, the latter are worthless but the first two can ruin your gas mileage, you should be able to make a diagnosis based on your recent fuel economy