So, my sister was given a 98 Blazer LS 4x4 4-door. It is throwing a P1153 code. She was told it's throwing the code because the cat was dented by a rock. I looked & I saw no dent but the angle I was looking from may have hid the dent. While I was peeking around I noticed the muffler is bad & there is a nice crack, that looks like a Harry Potter scar, in the Y-pipe. I've decided just to replace the whole system.

My research leads me to believe that the pipes are 2.5". I have found a new cat (Magnaflow 23455 $195) but nowhere can I find information on the diameter of the pipe. I have found a Y-pipe (Walker 50318 $129) but the outlet diameter is 2" & the tail pipe (Walker 45686 $42) is 2.5". Still looking for a muffler, I want good flow but don't want it sounding like Sherman Tank.

What do you think of the parts so far? Any suggestions or problems? All ideas are welcome. Thanks in advance.

 

Save your money on the converter. P1153 has nothing to do with the catalytic converter. The passenger side upstream oxygen sensor, (in front of the converter) is not switching correctly, (probably lazy and needs a new one). How many miles on the oxygen sensors?

EDIT: If there are any exhaust leaks upstream of the oxygen sensor, it could set the P1153.