I have an '01 1500 5.9. Original exhaust with 95k on it. Muffler is rusted out and pre-cat o2 sensor is bad and I'm having no luck removing it. Tried heating it, soaking it in pb buster, bought o2 socket (which I broke), cut wires to try a 12 point wrench which stripped out the nut, heated it more and tried my handy dandy vise grips and still can't get the damn thing off.

Anyways i'm about to get some exhaust work done. Was gonna go with just a cat back but considering I can't get the o2 sensor out and the muffler shop wants 100-180 bucks (depending on if I want a high flow cat or not) to replace the cat I guess I'll just get it replaced and have them put the new o2 in.

My question is what should i go with on a cat? I have a spectre c/a intake and plan on getting a hypertech programmer. Will be keeping the stock headers since I'm having no issues with them atm. Is it worth spending the extra 80-100 bucks for a high flow cat? I'm going with the flowmaster 40 muffler. Thanks for any and all advice.

 

Fix your plenum first before you replace the cat if you haven't totally screwed up the O2 wiring.

 

I used a 24" pipe wrench, and a hammer to get my O2 sensor out. Since I was replacing it, I didn't care how badly I trashed it getting it out, just so long as it came out.......

High flow universal cat, or Magnaflow direct fit would help you pick up a few ponies. Dodge Dude is correct though, need to address your plenum, or, you will be right back where you are now in fairly short order.

 

I did the plenum and intake mod about a month ago. Doing all this now because the plenum was so bad. In good news i finally got that pos O2 sensor out. Anyone know the ntk part number for the pre-cat o2 sensor? The guys at the auto parts store here don't seem too smart and keep telling me I have two.. when i don't... Thanks again for the replies btw.

 

They are looking at california emissions more than likely.

23139 is the number I come up with from advance auto. Pre-cat, right, except california emissions.