Is my Cat.Converter going bad?

[jbres]

I have a 2003 Tahoe with 132,000 miles on it. I have always had slight weird "muffling" noise through exhaust system during heavy acceleration. It has gotten worse now, and during acceleration, I have a weird "rattling" "muffling" noise traveling through my exhaust. It idles perfect with no exhaust noises if you stay idling.
I got under it and through visual inspection, my exhaust is in good working order.
Is it my cat converter gone bad?
Other ideas?

[jerem0621]

jbres wrote:
stopped by a local well known muffler shop today-they simply found that the heat shield above muffler was rattling on top of muffler causing the noise. They simply bent it back and away from muffler so they aren't touching anymore.
Wish things were always that simple!!!

GREAT NEWS... glad it was simple!

[jbres]

stopped by a local well known muffler shop today-they simply found that the heat shield above muffler was rattling on top of muffler causing the noise. They simply bent it back and away from muffler so they aren't touching anymore.
Wish things were always that simple!!!

[jbres]

ok thanks for the info!!

[jerem0621]

jbres wrote:
I am thinking about removing my Cat. converter and connecting in some new pipe to eliminate it altogether and seeing if this fixes the problem. We do not have Echeck here in Ohio anymore, so is there actually even any benefit to have a cat. converter?

Back in the 70's and 80's, yes great gains could be had. Today's Cat's are not very restrictive and help the motor operate within the design specs.

My truck had two o2 sensors per cylinder bank. One before and one after the Cat. Had I simply removed the cat the motor would have thrown a CEL.

I don't have to have my truck emissions tested in my county here in Tennessee either, but to sell my truck in the neighboring county it has to pass emissions or else the new buyer can't register the vehicle.

On top of that your emissions system is a federal requirement if not a local requirement. Your county or state may not require them but that has not stopped LEO's from doing visual inspections on vehicles to make sure the emissions equipment are there.

It will cost only a few bucks more to replace the cat than to straight pipe it.

My cat from ford was a two stage unit. Basically there are two smaller cats inline per side on my 5.4... total of four cats. Ford wanted something around $500.00 for the part.

My local Napa replaced the two small cats with one larger universal cat, repaired the damaged y-pipe from the pressure relief cut I made and installed a new o2 sensor for about $260.00. Not too bad.

oh, no CEL or emissions issue either. Truck passed with flying colors.

My recommendation is to stay legal, stay within spec, and replace the cat. Also, if you can confirm its actually the cat I strongly recommend NOT letting it go, as when it plugs up 100% the pressure will either find a way out by blowing a gasket or you could get extensive motor damage from the back pressure.

Thanks!

Jeremiah

[jbres]

I am thinking about removing my Cat. converter and connecting in some new pipe to eliminate it altogether and seeing if this fixes the problem. We do not have Echeck here in Ohio anymore, so is there actually even any benefit to have a cat. converter?

[jerem0621]

My F150 did this..started rattling .. Few wheeks later while driving down the road.....POW.... Followed by an incredibly loud exhaust sound from under hood.

My cat on the drivers side plugged 100% and blew the DPFE rubber hoses off and thankfully relieved enough back pressure to save the Motor.

Saws-all and 5 minutes and I had a sweet open header sound in front of the drivers cat which allowed me to get the truck to the shop.

Replaced cat, repaired hole and everything was happy happy happy again.

Thanks

Jeremiah

[Ron3rd]

eHoefler wrote:
Sounds like a baffle came loose in your muffler, a common issue in a vehicle with that many miles. When a cat plugs up, usually you will have a hissing sound and no power at all.

On the wife's old Infiniti QX 4 SUV, the cat developed some sort of noise on acceleration and was replaced under warranty. We weren't sure where the noise was coming from but they eventually figured it out after servicing the rear differential thinking the noise was coming from that area.

[jbres]

ironically today its not making the "rattling" muffling noise all the time. Just during acceleration at first, then goes away. I got under and looked over my exhaust system and confirmed nothing is loose at all

[keymastr]

Yes, your entire muffler needs replacing. There is no way to get inside and weld the baffle and if someone could it would cost more than the new muffler.

Your service light probably would come on if the cat was plugged because your exhaust would not be getting cleaned as well and the O2 sensor downstream of the cat would send a signal that it has high hydrocarbons. You can go to most auto parts stores and have them scan for stored codes. Sometimes it will store a code and fail to turn on the light.

If you do a lot of short trips where the engine barely gets warmed up it will rot your exhaust system faster and contaminate engine oil and tranny fluids faster. Avoid short trips if possible.

[2003silverado]

Dads 2007 avalanche had a "marble in a tin can" sound this past spring. We used a stethoscope to trace it to the cat. It was covered under the emissions warranty which is longer than the bumper to bumper or drive train warranty.

[jbres]

also, my check engine light is NOT on, so if it was the Cat converter would my service light be on?

[jbres]

so when a baffle comes loose do I need to replace my entire muffler?

[eHoefler]

Sounds like a baffle came loose in your muffler, a common issue in a vehicle with that many miles. When a cat plugs up, usually you will have a hissing sound and no power at all.