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Mitch8801

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Oct 6, 2019
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British Columbia
Hey Guys,
So recently I was on my way home and at a stoplight had a misfire in cylinder 2, and my exhaust sounded funny and fluttery, I was like 8 minutes away so I decided to drive it home and coast down hill. Long story short, I replaced the spark plugs, still had issues.
I checked my coil pack and it seems to be working fine. I swapped my injector 2 to cylinder 1 seeing if the code would transfer to cylinder 1, no codes.
I drove it around the block, the power seemed fine but noticed my front cat was glowing red so I went back into the garage.
Put in a new Mopar Crankshaft sensor as I had a code about 2 months ago for a bad cps sensor.

Here is a couple videos:
I also ordered a new o2 sensor as I also had a code prior, for 2/2 o2 sensor, haven't put that in yet.
After cps sensor install, new o2 sensor code P0135 pops up. that's bank 1 sensor 1.
Anyways
right now I'm thinking my front cat is clogged.
Any help is appreciated.
 
Last edited:

AndyG

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It's entirely possible , I just replaced both of mine on my 06 with a Flowmaster for 330.00 , and I an very pleased ..the media came loose in mine , threw a code, etc.

If the sensors aren't NGK , return them , and get NGK . Most others don't seem to work, just a heads up.

You can drop the Y and run a hair dryer down each and tell a lot .
 
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Mitch8801

Mitch8801

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It's entirely possible , I just replaced both of mine on my 06 with a Flowmaster for 330.00 , and I an very pleased ..the media came loose in mine , threw a code, etc.

If the sensors aren't NGK , return them , and get NGK . Most others don't seem to work, just a heads up.

You can drop the Y and run a hair dryer down each and tell a lot .
Gotcha, Yes my sensor I bought is NGK as that's what I read around on here for the only good replacement. I have a flow master muffler and I like it, Ill check out their cats.
 
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Mitch8801

Mitch8801

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You my friend have clogged cats.

Not uncommon by any means.

And yes, if you aren't using NGK / NTK O2 sensors, you're going to have other issues.

See this thread for info on that: The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread
You think it is possible that a clogged cat could cause my engine to misfire, it still is quite shaky but I'm not getting a code other than the O2 sensor code
 

Chris

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You think it is possible that a clogged cat could cause my engine to misfire, it still is quite shaky but I'm not getting a code other than the O2 sensor code

Oh yes, absolutely!

When my cats were clogged it was running like crap. Wouldn't go about 3000 RPMs, it misfired, and it was putting along almost like a steam engine at times.

The O2 sensors are providing all sorts of wonky feedback because the cats are clogged, so they are basically telling the PCM to do all sorts of weird stuff, thus why the vehicle is running so poorly.
 
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Mitch8801

Mitch8801

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Oh yes, absolutely!

When my cats were clogged it was running like crap. Wouldn't go about 3000 RPMs, it misfired, and it was putting along almost like a steam engine at times.

The O2 sensors are providing all sorts of wonky feedback because the cats are clogged, so they are basically telling the PCM to do all sorts of weird stuff, thus why the vehicle is running so poorly.
Thats good news as I was stumped what else to check. Im trying to find a pre cat kit for my 2002 TJ. I am only finding ones that fit 04-06, are they interchangeable?
 

Chris

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AndyG

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Gotcha, Yes my sensor I bought is NGK as that's what I read around on here for the only good replacement. I have a flow master muffler and I like it, Ill check out their cats.
Awesome, O'Reilly sales an oxygen sensor Ranch that accepts a 3/8 ratchet , which inherently makes it an offset design and once you get it positioned correctly gives you a little more leverage... It's well worth it to soak those overnight in penetrant .

The job goes easier if you drop the front shaft.

Don't connect it in the back first -work from the back forward

New bolts is great , if you will notice the bolts are designed to only tighten so far and I like to use full thread bolts to increase the clamp down since you don't have a gasket.

Good luck all the way sir.
 
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Mitch8801

Mitch8801

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Awesome, O'Reilly sales an oxygen sensor Ranch that accepts a 3/8 ratchet , which inherently makes it an offset design and once you get it positioned correctly gives you a little more leverage... It's well worth it to soak those overnight in penetrant .

The job goes easier if you drop the front shaft.

Don't connect it in the back first -work from the back forward

New bolts is great , if you will notice the bolts are designed to only tighten so far and I like to use full thread bolts to increase the clamp down since you don't have a gasket.

Good luck all the way sir.
Thank you sir, you think the 04-06 cats will work for my 02
 
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Mitch8801

Mitch8801

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British Columbia
That'll cause a check engine light.

Clogged pre-cats can definitely cause misfires, it happened to my 04.
That'll cause a check engine light.

Clogged pre-cats can definitely cause misfires, it happened to my 04.
Thats good to hear Jerry, Did they change anything with the exhaust system in 04-06 compared to 02? I can't find a good deal on 02 cats
 
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Mitch8801

Mitch8801

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Update: I had to chop the pipe to remove the Y Pre cats and unfortunately it’s not them, the insides of the catalytic converters look fine.
85DAAD5B-F543-4446-A841-81FB9A1B8716.jpeg

so I guess bank 1 was running rich as the cat was red hot.
Guess it’s back to the drawing board. Any ideas?
 
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Mitch8801

Mitch8801

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I used to work in a muffler shop. The prime reason for glowing cats is fuel mixture problems.
Yup, gotta be running too rich in bank 1, what could it be? I’ve put new plugs, and 3/4 o2s are new. The only thing that’s left is coil pack and injectors? I’m going to swap my buddy’s coil pack in to test the coil pack.
 
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Mitch8801

Mitch8801

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UPDATE: Good news! Turns out it actually was the coil pack. Swapped In my Buddys coil pack and the jeep ran mint. I will be doing a quick little how to post on the repair and the symptoms