KZen

I have a Honda civic 2005 that makes a single clunking noise. It happens only occasionally, specifically when I start to brake, accelerate or sometimes when I let go of the gas. When the clunk happens, it seems to be coming from either beneath the floorboard or from the rear of the car. Sometimes it causes the car to pull back, almost like a transmission kick or a backfire. Because it only happens occasionally, it has been difficult for mechanics to reproduce it when I bring it in for a diagnosis. One mechanic did check the suspension and said it was fine.

On the other hand, I have a motor mount that needs to be replaced. It has caused the engine to raise up when shifting to reverse, as well as creating a loud clunk noise when I shift to reverse. I believe it is also the culprit of the vibration in the car. After doing some research online, some believe it can lead to clunking when decelerating or accelerating. What do you guys think?

Any help would greatly be appreciated.

NDNV

Sure could be the bad motor mount causing the symptoms you describe. Swap it out and report back.