Accelerated hard now the engine runs rough and has a rough sounding idle as well?

Tiny
2006KIADRIVER
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  • 2006 KIA OPTIMA
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 164,900 MILES
Now the engine runs rough and has a rough sounding idle as well. Acceleration is slow. The rpm meter is displaying in a normal way. When I accelerated too hard as I was driving, I heard the engine make a higher pitched roaring sound compared to its usual operation during acceleration, just before white smoke appeared from the air vents. The ac was off. I can still drive the car, it runs. The mph meter has very inaccurate indications, when I press the acceleration pedal, it reads as though I were always very very lightly pressing it. It will give a reading of the speed of course, but it seems as though it is not picking it up all the way.

Additionally, a day ago I drove over ice while turning and skidded off the street onto a lower area, and the front left wheel had visible damage as a result. It felt like a crash, but I drove out and went on my way. Too much snow to see if I hit anything. A portion of the tire bulges out
at the side of the tire now, and the rim is dented in the same spot. No repair was made. Turning the steering wheel to its extreme clockwise makes a squeeling sound and causes the car's front left wheel to turn quickly and mildly in different directions until the steering is returned from the extreme. It seems to do this same thing but to a lesser extent when driving straight and forward. No known leaks, although I have not thoroughly inspected under the hood. I haven't been to a mechanic. The catalytic converter was stolen before I first bought the vehicle, I replaced it with a new one months later but the pipes were not sealed together to contain all exhaust fumes. No check engine light appears now, even after the main incident mentioned above had occurred.

I can idle, drive around, turn the car on like normal with no problem otherwise.
Wednesday, April 5th, 2023 AT 12:18 PM

13 Replies

Tiny
KEN L
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We only handle one problem per thread so please start a new question over the tire problem. Can you please shoot a quick video with your phone so I can hear the engine noise? That way I can tell for sure what's going on. You can upload it here with your response. In the meantime, check the engine oil and the coolant level when the engine is cold only.

This video will help:

https://youtu.be/GSE9skKnOgY

Also, this guide may help as well:

https://www.2carpros.com/articles/engine-noises

and

https://www.2carpros.com/articles/rattle-noise

I need to hear what kind of noise the engine has to tell you what's going on. Also, I would like to hear the engine cranking over.

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Wednesday, April 5th, 2023 AT 1:25 PM
Tiny
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I added the information about the other problems in case it helped to know, as they may have contributed to the engine issue. Here is the video you requested.

On the same note as above, I changed the spark plugs myself some months ago without being precise or equal about tightening them.
With the catalytic converter added, the engine was, prior to the incident, quieter than it is now, as what can now be heard in the video.
The engine now sounds like if I hadn't attached the catalytic converter, with it being this loud again. The attachment of the converter I then created had connected the flange of the manifold to the converter and, more importantly, to the muffler.

I'll check out the links you gave.

I don't think the oil has anything to do with it, nor the coolant. Everything was fine earlier. I also changed the oil about two months ago, but I'll check the oil. The coolant reservoir tank was topped on October of last year, I'll check the levels. One thing I haven't changed is the oil filter, which was due to be changed a couple of weeks ago.
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Wednesday, April 5th, 2023 AT 3:13 PM
Tiny
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The video didn't provide sound during the acceleration that I gave the car.
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Wednesday, April 5th, 2023 AT 3:15 PM
Tiny
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Okay, I've checked the motor oil and coolant fluid. The dipstick for the oil shows that oil levels are at the full mark, and not a millimeter below. The color of the oil on the dipstick looks lighter than coca cola but certainly not as light as honey.
The coolant in the tank seems to be at a high level. In the radiator tubing, it is also at a high level. I dripped some coolant fluid drops from the radiator cap to make sure that it was actually the level, and it was. The color of the fluid seems slightly dark green, but still transparent.
Those two areas checked seem okay to me.
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Wednesday, April 5th, 2023 AT 3:38 PM
Tiny
KEN L
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Thanks for the video, that does sounds strange, the video sounds cut out when you revved it which is what I needed to hear. Also can you take the video from under the hood and then have a helped rev it? That would be great, it also sounds like part of the exhaust system has fallen off or is disconnected or you have a rod knock, I can tell more with the next video.
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Thursday, April 6th, 2023 AT 11:14 AM
Tiny
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Here's a video of me revving it with the hood open. I had no helper so I couldn't get a front shot of the engine.
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Thursday, April 6th, 2023 AT 2:12 PM
Tiny
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The video sounds decent, but if more needs to be done then I'll try.
More info in case it helps. The rpm meter stays below 1 and above 0 when the engine is running on idle and on unaccelerated driving.

I curiously want to know what that white smoke was. When it came through the ac vents, just after I pressed down hard on the pedal and caused this problem, it did not have a recognizable smell. And it disappeared shortly after I let off a good deal of pressure on the pedal. The car does not easily accelerate above 50 mph or so anymore without struggling greatly.
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Thursday, April 6th, 2023 AT 2:24 PM
Tiny
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I checked the spark plugs this morning. Nothing really unusual, just some oil on two of them. I checked the exhaust system under the hood. I'm no expert, but from that angle nothing seemed broken, detached or unusual. I lifted the car and checked the rest of the exhaust underneath. The catalytic converter was discolored. The rest of the exhaust seemed normal.
I drove around with, again, a reduced ability to accelerate and a loud engine.
When I started accelerating at over 3 x1000 rpms and maintained consistent speed, the smoke gradually appeared again. When the speed was over 40 mph and below 50 mph, but the rpms were between 2.5 x1000 and 1.5 x1000, the smoke didn't appear.
But it smelled like burnt pancakes when it did.
My best guess from all of this is that when I gunned it a couple of days ago, some oil went down through the exhaust and ignited the filter in the catalytic converter, and this caused the smoke to appear. The filter is now burning on occasions, I'm guessing. And the rough idle and poor acceleration is consequently due to the poor performance of the converter which is also affecting the oxygen readings and thereby affecting the engine performance.

Your diagnosis is welcome.
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Saturday, April 8th, 2023 AT 9:45 AM
Tiny
KEN L
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Thanks for the video. "Smelled like burnt pancakes" I have not heard that one before, thanks for that ;). Please double check the spark plugs either one has fallen out or the center porcelain has shot out of the main body (screw part). If the spark plugs are okay the engine sounds like it is hurt (rod knock etc, ). It may be worth it to remove the serpentine belt and start it as well to make sure there is not an engine accessory causing the noise. Please let me know.
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Monday, April 10th, 2023 AT 11:24 AM
Tiny
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When I checked the spark plugs previously, I took them all out and inspected each. They seemed in decent shape, and nothing broken of them. I threaded them all back in and drove about 20 miles that day, the problem was still there, however.
I will have to check the engine with the serpentine belt removed on some day after tomorrow. I have a circumstance due tomorrow that might take up a lot of my time.
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Monday, April 10th, 2023 AT 4:22 PM
Tiny
KEN L
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No problem, let me know. I hope the noise is not an internal problem. I had a thought that maybe you dented the oil pan. Can you look under to see if that is the case?
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Tuesday, April 11th, 2023 AT 11:06 AM
Tiny
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I haven't checked but I'm thinking its rod knock. If it is, then would fixing it later rather than sooner possibly destroy the engine and immobilize the car?
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Tuesday, April 11th, 2023 AT 11:48 AM
Tiny
KEN L
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Yes, you should stop driving the car if you want to repair that engine.
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Thursday, April 13th, 2023 AT 9:41 AM

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