2010 Honda Civic Engine Revving

Yesterday I noticed a problem with my vehicle I had never experienced before.

When I start the car, the engine makes a revving sound that is louder than usual. Then when I’m driving, whenever I press down on the accelerator I again hear a kind of revving sound that is louder than the norm. The car does accelerate, but it feels like it’s laboring to do so. It feels kind of like the moment just before a car switches into the next gear. So, like it’s trying to shift but can’t quite get over the hump.

I called the place that usually services my car, and they recommended a place that specializes in transmissions.

That evening, I drove it a little bit more. The symptoms persisted, but (could be my imagination) it seemed maybe 75% as bad as earlier.

Today I took it to the transmission place. The guy called me a few hours later, and reported that there was definitely no problem with the transmission. He speculated maybe there was a clog or some problem with the exhaust, but he doesn’t work on that and was just taking an educated guess.

I did notice, driving to the shop and later driving back, that the problem again seemed to be lessening. Today it seemed maybe 50% as bad as when it first started yesterday.

It has about 76,000 miles on it. I get all the routine preventive maintenance done on it that my regular shop recommends. I have not had any other problems of note with the vehicle, certainly nothing that I would think is related to this.

Any thoughts on what I might be dealing with? What should be my next move? Am I risking doing a lot more expensive damage to it by driving it? Should I just monitor it and see if the symptoms continue to gradually lessen?

If a converter clog is suspected that can be easily checked with a vacuum gauge. If this problem is not related to an exhaust clog then one has to suspect slippage in the transmission (automatic) or slippage in the clutch (manual transmission).
If the engine seems a bit balky while trying to accelerate it with the car being stationary then a clogged converter is certainly possible. I’ve always likened this sensation to stepping on a bag of marshmallows… that’s always been my impression of gutless engine revving.

If this ia converter clog then it needs to be remedied as it will only get worse over time. It’s at least possible that at some point the clogged converter could cause engine overheating and damage the engine to one degree or the other.

Thank you very much for the response.

I’m leaning toward taking it to a place that works on exhaust systems next.

It’s an automatic transmission. Do you think it could still be a transmission issue despite what the transmission shop guy told me? Is that the kind of thing that sometimes doesn’t show up with the tests or whatever that such places use?

The other fact I meant to mention in my initial post is that there are no check engine or warning lights on.

I just thought of something else that could be relevant.

In the last couple months I’ve done some driving on dirt roads. Not a great deal, but normally I don’t do any. Is that the kind of thing that can kick up material that can clog the catalytic converter, or for that matter cause some other issue relevant to the symptoms I’ve described?

Since the problem seems to have lessened at least modestly in the last day and a half, can exposing the car to dirt and dust like that cause temporary issues and then the dirt gradually works its way out? (Probably a dumb question, but I know next to nothing about these things.)

Look at the air filter. If it is too dirty, that would reduce air entering the engine and could cause the laboring effect you mentioned.

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The catalytic converter is a closed part that is not exposed to outside dirt. It doesn’t get clogged that way.

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I called my usual shop and told them the transmission place ruled out that it’s the transmission. I asked them if they could check the exhaust system and the air filter, or any other hypothesis they come up with. The soonest they can look at it is Monday; I plan to bring it in then.

I drove it a little today. I was hoping it would continue to improve, but it felt about equal to yesterday. At least it didn’t get worse. I’ll only drive it sparingly between now and when I take it in.

So here’s the resolution of the story:

On Monday I dropped if off. The shop called me at the end of the day to report that they had diagnosed the issue. They said the muffler had “rotted clear through” where it attaches to whatever it attaches to, and so I need a new muffler plus the clamps or nuts and bolts or whatever the connective material is.

They did the work for me on Tuesday, and I picked it up. It cost almost exactly $400. It seems perfectly fine now.

Interesting that a major part can fail like that and not trigger any kind of check engine warning lights.

Thank you to everyone who responded in the thread.

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The muffler is downstream of all the emission sensors, hence no CEL.
I now question the competency of the shop that does your routine service. A rusted out muffler, exhaust, or tailpipe should be easily visible during an oil change.