Bad muffler creating vibrations/pulsing?

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HoosierJeeper

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Getting a pulsing/vibration feeling on acceleration, can definitely hear an exhaust leak. Up near the engine bay it sounds normal, walk around it and it's definitely louder at the muffler. Can a bad muffler cause a pulsing/vibration feeling while driving too? Engine seems to run fine, at WOT I don't feel it, it's more noticeable in the moderate load range. Just cruising it seems smoother.

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KJowner

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That sounds more like it's missing on 1 cylinder to me, or a massive leak on the exhaust manifold, but as it's quite at the front I'm going for a miss.
 

HoosierJeeper

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That sounds more like it's missing on 1 cylinder to me, or a massive leak on the exhaust manifold, but as it's quite at the front I'm going for a miss.
Would a miss give me a CEL? Not getting any codes from it now.
 

KJowner

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Would a miss give me a CEL? Not getting any codes from it now.
It should do, depending on the cause. I'd pull the plugs out and see if any of them are wet for a start. Or if you have a laser thermometer, one of my favourite diagnostic tools, check the manifold temperature at each port, you can easily see if one cylinder isn't firing.
 

LibertyTC

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HJ- I'd definitely would want to get it up on a lift for a good inspection while running !
Hopefully it just needs a muffler ?
 

HoosierJeeper

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HJ- I'd definitely would want to get it up on a lift for a good inspection while running !
Hopefully it just needs a muffler ?
That's what I'm hoping! Last Friday the upper radiator hose blew and gave everything a good soak. Drove fine after, parked it for the weekend and then drove it yesterday and got a flashing CEL and was running bad. Turned right around and pulled all the coils out, some had gotten wet so dried them off and the CEL is gone now. Engine feels smooth, just feel that pulse/roughness from somewhere. Muffler has been getting louder for the past few months, maybe it's a coincidence that it finally fell apart inside or something, but also I suppose wouldn't rule out a slight misfire, but have trouble believing that since there's no CEL. For as rough as the exhaust sounds you'd think there's be a code if there was a misfire.
 

LibertyTC

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HJ- I'd also consider new KJ copper core spark plugs, NGK ZFR6F-11G if they have not been replaced in a while (35k Miles)
Here is the top rad hose part number for you as well. Hopefully still available I hope !!
Luckily I replaced my upper rad hose before it spewed everywhere. ;)
Only use Mopar Hoat Coolant or Zerex G05 in our Jeeps !
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HoosierJeeper

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HJ- I'd also consider new KJ copper core spark plugs, NGK ZFR6F-11G if they have not been replaced in a while (35k Miles)
Here is the top rad hose part number for you as well. Hopefully still available I hope !!
Luckily I replaced my upper rad hose before it spewed everywhere. ;)
Only use Mopar Hoat Coolant or Zerex G05 in our Jeeps !
You must be registered for see images attach
Got the new hose already and it's full of Zerex G05, got all the store had LOL. Old hose was a Napa EPDM hose, 7 years old. Spark plugs are the right NGK ones, they have just under 30k on them.
 

u2slow

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If the muffler is old, it can be rusting, breaking-up and collapsing internally. I'm onto the 3rd muffler now in 12 years. (well, the 'middle' muffler lasted about 9 years.)
 

HoosierJeeper

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If the muffler is old, it can be rusting, breaking-up and collapsing internally. I'm onto the 3rd muffler now in 12 years. (well, the 'middle' muffler lasted about 9 years.)
How did it sound compared to my video?
 

u2slow

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My stock muffler didn't sound like your video - was still dead quiet. It was rusted through externally, so I changed it. The next two have been louder/smaller aftermarket - a flowmaster copy was the 9 year one.
 

The Fixer

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The original muffler on our '03 rusted through at the seam back in 2017, it had a similar sound to your video. The hole was on top, so we could hear it, but not really see it.

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After that, we had a Dynomax catback on it until 2022, which my son squashed wheeling some Blue trails at AOAA. He replaced that one with an MBRP catback, which sounds great.
 
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