I could not word this correctly for the search, sorry for what I am sure is a duplication.

So I did the summit universal magna flow cat replacement and now my downstream O2 sensor keeps tripping the CE light.
At the same time as the cat I replaced the upstream sensor with a bosch and kept the original down stream which is an NGK.

I never had a problem with the down stream sensor before replacing the cat.
Now during normal driving speeds the O2 does not trip but it does at an idle or when I give the gas a quicky to get in and out of the not built for a Ram parking space at wally world.

Let the troubleshooting begin

 

mine did the same thing, but min was throwing the code when moveing consistantly at 65mph+. i shut off te truck, and turned it on, and the CEL was gone. Mines an OBD1 though.

Your best luck though is just to change the sensor andsee where that leads you. and make sure its OEM. ive heard of universal 02 sensors tripping off the lights.

 

I have also heard that the bosch and ngk to talk well?

 

If installing a new one does not help, you can do the spark plug non fouler trick. Part # 42002 in the HELP! section at your loacal parts store.

 

Which magnaflow cat did you get?

I had this exact issue until recently. The 94XXX series Cat is not big enough for our trucks, though it is listed as a good P/N. You need a 99XXX model cat. it has more precious metal inside to combat the excess ethanol that has been added to gasoline. There is actually an internal magnaflow memo out to dealers of their parts about this. Basically it states that if you try a 94XXX series and it trips a code, move up to the 99XXX and charge only the difference in price.

This is what my exhaust guy told me, showed me the email he got from magnaflow direct about it, and was really awesome about replacing it. No labor charge at all, just the difference for the more expensive cat.

 

Yeah, thanks to aim's help a while back I went from the 94xxx that tripped a cel in 6months to 99xxx and haven't had a problem yet.... well with the cat at least lol idk what cel your throwing, but I threw a 0420 for cat ineffeciency. Are you throwing that code or a 0138, or something else?

 

id just run the non fouler trick, or just remove the cat entirely and do the non fouler trick as well.

 

Thanks guys,
Here is what I have.
http://www.summitracing.com/parts/MPE-23285/

 

ok ive done some research on the cats looking at all their statistics.

the only thing ive noticed that are different is the overall diameter. all the other stats match up on different cats.

So the way to fix this problem that i can see, is try replacing the 02sensors again. and if that doesnt work. do the non-fouler trick. but there really isnt a point, that i can see, on why you would have to get a different cat

 

Nobody else has heard of any issues with mixing the two brands of o2 sensors?
Also I am an electronic engineer so I could more then likely build a sim easily enough, anyone have a schematic?
I am not getting the no fouler trick anybody got a pic of the finished product?
Seems to be nothing more then a spacer to get the sensor out of the pipe?