I have a 5.9L auto and I've noticed my cat has been rattling abit. Also when I get on the throttle or under a heavy load my temp gauge will go up to 210ish. Could this be a cause of a bad cat? Also can anyone point me in the right direction for a high flow aftermarket. Direct fit from the donuts down. I have a aftermarket muffler so I can weld it at the other end. I only have 1 o2 sensor and it's mounted to the cat. Or is there a effected method to tear the guts out. Cause how it's mounted I don't think I can smash it out with a rod without completely removing it. And I think it's easier to to just order new

 

Magnaflow makes 'em. Available from Summit, or Jegs. Bolts right on.

I think you have cause and affect backwards though. The bad cat is causing the engine to run hotter under load.

Have you fixed your plenum yet? That tends to kill cats. (not fixing it. )

 

No I havnt done my plenum kinda scared. The truck only has 50K original miles. and Idk if the plenum is bad or not. I can't find a mechanic I trust. If I get the the kit with a different plate would the dealership still do it? If it's bad maby I should just cut the cat out and pipe it till I can get it fixed first. I'm not worried about inspection I know acouple people who will lick and stick me a sticker. I can just mount the o2 Back In. My o2 is right at the very front of the cat. So gutting it shouldn't affect it. Or power or anything correct?

 

You do have to weld the one pipe on.

 

The O2 sensor right in front of the cat is the critical one, gutting the cat won't effect it at all. If your cat is failing, cleaning it out may give you MORE power...... the engine is just a big air pump, if there is a restriction coming in, or going out, that costs you power.

Dealer is going to be quite expensive for such a job...... Take a quick look down your throttle body, see if you see any oil in there.

 

Yeah I'm gonna try this weekend gutting the cat. Gonna try the cut and peal method because how it's mounted. Usually I use a big bar and smash it out and use the motor to push it out. But there's acouple bends right there. Also replace the o2 sensor with a new one it can't hurt while I'm in there if I happen to mess up the shell. can I just run a straight pipe and weld the o2 sensor in?

 

For what its worth, flowmaster also makes a stainless high flow cat + y pipe for our trucks....that's what I have on mine and am very happy with it. Fit like a glove. Got it from amazon...for under $300 if I recall correctly. Exact price depends on the year of your truck since the exhaust changed slightly in 2000

 

X2 Just replace it and forget it! It's not worth the hassle and the check engine light. Had mine in about 2 1/2 years so far and not a single problem. New cat and two new NTK 02's with stainless bolts on the exhaust.

 

Mine is obd 1 so I won't get a check engine light from an o2 sensor. I only have 1 sensor and it's before the cat.

UPDATE: I went ahead with the project last night. I cut 3 sides of a square out of the cat. Bent the piece up took everything out. Folded the piece back down and welded it tight. Then re attached the heatshield so u can't see my welds.

This morning I went for a drive with my work trailer[7000lb] and I can notice a slight difference. power is slightly better. And so far motorTemps are staying normal. But It was only 70 degrees out. I don't like the sound of the truck so I'll definitely be getting something different. I'll run a full system with a new cat but due to the unknown status of my plenum I'm gonna run it like this till I can do a huges kit. I'm not loosing oil but the plate will need done eventually in its life. I don't wanna burn another cat out if that was the problem.

From first impression I would say it was a success but only time will tell

Will I have any issues leaving it like this for a while? It's obd 1 so I shouldn't have any problems with o2 sensors or check engine lights.

 

Nope, PCM will run the engine as it sees fit. NOT having the clogged cat will only help you.