Thumping/clunking noise when under load

Tiny
IAN GRIMES
  • MEMBER
  • 2004 KIA AMANTI
  • 3.5L
  • 6 CYL
  • AUTOMATIC
  • 115,000 MILES
I do have bad motor mounts but this seems as if something is hitting something. This only happens when my foot is at a certain point on the pedal. If I accelerate or let go of the pedal the noise stops. What could this be? It also affects my performance. If I try speed up I have loss of power. Here is a video of the noise: https://www.youtube.com/watch?v=oDb7l0dzIjQ

Note: This does not happen every time I accelerate. Only maybe 40% of the time when I need to speed up after switching gears. The video intensifies at the end.
Do you
have the same problem?
Yes
No
Monday, September 17th, 2018 AT 5:08 PM

12 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi and thanks for using 2CarPros.com.

I listened to the video and it sounds like the sound is from the front. First, I would carefully and safely lift the front end from the ground. Check for excessive play in both front axles. Also, confirm there are no loose steering components or a loose wheel.

Take a look at this link. It describes the symptoms of a bad axle/CV joint.

https://www.2carpros.com/articles/symptoms-of-a-bad-cv-axle-joint

Let me know if that helps. Also, let me know if you feel the vibration in any part of the vehicle such as the steering, seat, floor.

If you find a bad axle, here are general directions for replacement.

https://www.2carpros.com/articles/replace-cv-axle

Take care,
Joe
Was this
answer
helpful?
Yes
No
Tuesday, September 18th, 2018 AT 5:37 PM
Tiny
IAN GRIMES
  • MEMBER
Okay, I do feel vibration in the floorboard as it is pounding. I also took it into a shop to have it inspected today at no cost. When they went to inspect it, me and the mechanic noticed that one of the ignition coils has a tiny spark to it! Which means it is no good. That is probably why I have a misfire as well.

Considering this noise only happens when the car is under load, can a bad ignition coil/misfire cause the pounding sound I am hearing? The mechanic said this is probably why. I would love to hear back!
Was this
answer
helpful?
Yes
No
Tuesday, September 18th, 2018 AT 6:53 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Welcome back. A misfire can cause a noise. However, it should have also set the check engine light. If the light is on, repair the misfire and see if the noise goes away. It may. If the check engine light isn't on, I question a misfire. Regardless, what I heard on your video did not sound like a misfire. Rather, it sounded like something was loose. Did the tech check front end components, axles?

Please keep in mind, if something is sparking at the coil, it needs repaired.
Was this
answer
helpful?
Yes
No
Tuesday, September 18th, 2018 AT 7:37 PM
Tiny
IAN GRIMES
  • MEMBER
So I actually did start notice the sound ever since it rained and I got a misfire. The light came on but I have cleared it and it never came back since. But it still feels like it is misfiring due to car obsessively shaking and loss of power.

I ordered a new coil and hope to see it by the end of the week. But yes, I believe they looked at the front suspension, at least I hope so. Why would loose suspension part cause lack of power?
Was this
answer
helpful?
Yes
No
Tuesday, September 18th, 2018 AT 8:13 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Honestly, it would not affect your performance. However, often times when something like this happens, it seems like a loss of power. If the coil does not fix the issue, let me know. At that point, we will need to make sure the catalytic converter is not plugging.
Was this
answer
helpful?
Yes
No
Wednesday, September 19th, 2018 AT 5:33 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
After thought. Take a rubber mallet and tap on the catalytic converter. See if you hear anything rattle inside. The guts of the converter may have come loose and causing a sound and loss of power. (Regardless, if the coil is bad, it still needs replaced)
Was this
answer
helpful?
Yes
No
Wednesday, September 19th, 2018 AT 5:35 PM
Tiny
IAN GRIMES
  • MEMBER
Thank you will do. After I perform both of those tasks (tapping catalytic converter and replacing coil). I will get back to you. Please hold.
Was this
answer
helpful?
Yes
No
Wednesday, September 19th, 2018 AT 8:18 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I will watch for your reply.
Was this
answer
helpful?
Yes
No
Friday, September 21st, 2018 AT 8:39 PM
Tiny
IAN GRIMES
  • MEMBER
I guess the coil will not be here until Wednesday. I am doing the best I can to not take it very far. I thought as I wait I would give you a list of all the possible problems I have with this car since buying it two weeks ago. Here they are: Head gasket leak. Bad control arm. Exhaust leak. Bad motor mounts. Knocking rod. Bad misfire. ESP and ABS light sometimes come on at same time. Now, I do not know if there is really a knocking rod. One mechanic said I did the other said I did not. Maybe you can know if any of these things can cause what you have heard?
Was this
answer
helpful?
Yes
No
Saturday, September 22nd, 2018 AT 6:23 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi again. I listed again to the video. I do not think that is a rod knock. To me it sounds like it could be a broken coil spring, bad strut mount. However, since it only happens at a specific RPM, that sort of eliminates the idea it is suspension related. However, you mentioned a control arm. If the bushings are bad enough or a ball joint is shot, it could make noise.
Was this
answer
helpful?
Yes
No
Saturday, September 22nd, 2018 AT 7:17 PM
Tiny
IAN GRIMES
  • MEMBER
Hello, so I got my coil and it fixed it! I do not see how this has happened. Maybe the car was under too much load and due to my motor mounts, the engine just started shaking? So weird. Granted I have not tried to hit the freeway yet so hopefully it is all good there as well.
Was this
answer
helpful?
Yes
No
Tuesday, September 25th, 2018 AT 6:19 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Welcome back. That is great news. It must have been misfiring and causing something to vibrate. Regardless, I am glad it is fixed. Let us know if you have questions in the future.
Was this
answer
helpful?
Yes
No
+1
Tuesday, September 25th, 2018 AT 6:59 PM

Please login or register to post a reply.

Recommended Guides