symptoms of a clogged exhaust

[Guest]

my truck is starting to run rough again. it's doing this kind of intermittent lurching thing. it's been increasing in frequency.

i wonder if this might be due to the exhaust getting clogged up again. this has happened once or twice before with similar symptoms.

i'm wondering if i should cut off the cat and muffler and see what happens.

[Double D]

Oh man, tell me you didn't fall for the old "banana in the tailpipe" gag again, did you?

[tonytheskin]

cut that cat out...you don't need it in Walton County.

[Guest]

well sunday i am going to cut out the cat and gut it.

not exactly sure how i'm going to get it back on there, though.

apparently 3" exhaust pipe isn't a standard size that autozone has.

[Highbars]

A plugged exhaust usually is not intermittent.. Plugged exhaust will cause power loss under load conditions or higher R's.. It can only take in what it can get out .. It is usually best to qualify all the systems you can first.. Ignition , fuel, Power and grds, vacuum...etc. Isn't this an '89 chev.? If so does it ever stall going around a corner sometimes?

[Guest]

ignition should be fine - i replaced rotor, cap, plugs and wires last month. ECM is only about a year old.

i cut out the cat today. it was stopped up to a degree. for now i replaced it with some 3" metal dryer vent from home depot. i'll drive it around some later and see how it goes.

no stalling around corners, usually.

[Guest]

ok so yeah... back pressure ruptured the dryer vent. had to use some flashing to fabricate some pipe until i can get it to the shop.

it does seem to be running a little cooler, though!

[LMS]

I have seen a cat come apart and the chunks went down and stopped up the muffler.
I have only seen this once though so can't say that that's your problem. How does the cat look inside? If it looks broken that may be your problem.

[Guest]

it looked like a little grid, most of which i could see through.

about 25-30% of it looked stopped up.

[Guest]

so the muffler was full of debris. i ended up getting a 3.5" diesel-grade exhaust system for $150.

[Morella]

Keep in mind that if your EGR system is not functioning properly, your catalytic convertor will be damaged. If I could remove my cat, I would, but I would never put one that was designed for diesel engines on.

-denise

[Guest]

wasn't a diesel cat, just pipe and muffler.

i should take a look at the EGR stuff too, i suppose

[Morella]

If you don't have a cat, you don't need EGR. I was just concerned about a diesel cat with a gasoline engine. Evidently they're not very tough, because we had to have a mod installed to use engine coolant to cool ours.

-denise