Help! Chatter/Rumbling at 1100 RPM

[JerZDevil81]

OK, so hopefully someone can help me out cause I am going nuts.

01 3.0 5spd

About a month ago I did a muffler delete and ran a pipe from the cat back and have it coming out in front of the passenger rear tire. No problems until Friday. I have the rumble/chattter at 1100 RPM and when starting cold (after it sits all night). Got underneath, held down the pedal till 1100 rpm and did a screwdriver to the cats. One didn't sound right, the 3rd cat (the 2nd one from the rear). Its NOT the heat sheild (although I do have that wonderful noise from 3000-3100) but this is more of a rumble. I did put a quart of Marvels Mystery in about 2 weeks ago, but when im in the engine bay it does not sound like an engine noise. I also held the screwdriver to the tranny but didn't hear anything.

I changed out the tranny fluid just for shits and giggles, it REALLY needed it anyway. Old fluid was dark as night and prob had never been changed. Didn't help the chatter though.

ANY ideas?

 

[PanamaExpat]

Can you feel it when you are driving or is it just noise?

 

[JerZDevil81]

It is present when driving or in neutral. Can feel it at idle although it is real prnouced at 1100. Less noticable when driving prob due to road noise. Truck does not "feel" any different when driving, not like it is bogged down or misfiring or anything. I tried to take a video but you cant really make it out. Felt like she wanted to stall on me when I first started it up this morning.

I've read that a bad tank of gas could do it, and I did get gas from a different station than usual, although it was Sunoco and not a "cheap" place.

 

[JerZDevil81]

http://www.youtube.com/watch?v=ZCdr2TFyMDI

If you listen close you can hear the rumble... thats me holding it at 1100.

 

[PanamaExpat]

Is it possible that the inside of your cats are rusted loose? I can't make it out for certain but it sounds like exhaust. I put your vid in the page for you.

Maybe get a recording from under the truck. Some things are tough to diagnose when you are not there in person.

 

[JerZDevil81]

So hard to tell from underneath. Screwdriver test kind of worked. But it just started all of a sudden. Maybe when I was trying to test for the heat shield I hit the cat too hard?

You can kind of hear it at :52, 1:17 and then towards the end from like 3:30 on... also, I havent liked the way its been shutting down like at 3:55


UPDATE: I relistened to it and you can tell shes struggling at 2:58.... WTF IS THE PROBLEM lol

 

[PanamaExpat]

Hate to have to say this but maybe one of these younger guys got better ears than I do. Too much loud exhausts, fire arms, and rock n roll as I grew up.

I couldn't really pick anything too out of the ordinary out of that vid. Maybe ADSM will happen in and give it a whirl.

 

[wildbill23c]

Are all of your exhaust connections good and tight? Sounds like something is just lose. Go back and check all of your bolts and make sure they are tight. Other than that I don't really hear anything that would cause alarm for me. My Jeep always had an exhaust rumble but it also had a flow-master exhaust system which has a tendency to rumble anyways.

 

[JerZDevil81]

The only thing that was taken off was from the cat back. I used the stock replacement pipe for a long bed and got a new gasket and bolt set to bolt it to the cat. I then used a 90" and a universal hanger. Setup has been this way for 3 weeks with no problem. Pictures of my setup may help I suppose.

I did bang on the cats with a rubber mallet to find my heat sheild vibration. Maybe I screw it up hitting to hard on it?


This sounds more like a knocking but not from the engine... its a scary thought, but I PRAY its not my throwout bearing...

 

[PanamaExpat]

Throwout bearing generally stops making noise when you release the clutch as it is no longer spinning. Or shouldn't be anyway. But anyhow let's hope it isn't a clutch problem as they are no fun to change.

 

[JerZDevil81]

Master/Slave isnt leaking, clutch is at the top and it shifts smooth. Shifts even better now that I changed out the fluid with Mercon V. Fluid was dark as night.

Makes the noise whether in gear, netural, driving, or idling. I'm gonna redo the exhaust and pray it isnt a cat.

I started another thread, but any reason why 01-03 have 4 cats and 04+ only have 3?

 

[adsm08]

Didn't listen to the video since I am at work. The description does sound like a collapsed cat. Get under and pound on them with the heel of your hand. They should not rattle or sound hollow.

 

[JerZDevil81]

I hit the cats yesterday with a rubber mallet and didnt hear anything out of the ordinary. I couldnt even pinpoint where the heat sheild rattle was from. I held it at 1100 and listened with a screwdriver to the cat (2nd from the rear) sounded a little funny. Any reason 04+ have only 3 cats? Could I use one of these or is the range different throwing off the o2?

I'm going to end up take the pipe off that I just put on, but I can't see how it would cause this.

 

[PanamaExpat]

If it is only exhaust noise... I'll give you the standard TRS answer... Turn up the radio.