Noise from front driver wheel area, pedals?

I have a 2002 Buick Century which I believe is forward wheel drive and auto tran.

Note that the issue below does not seem to affect the driving or braking quality as yet.

It has started making a clunking sound at times when the brake pedal is released and also at times when the accelerator pedal is released lightly. It almost sounds like something is clicking into place but does not quite fit right. This is a recent change, has not always occurred. About a month ago, after this was noticeable, I also had to slam my brakes hard to keep from hitting a short stopping motorcycle, and it made a Loud thunk noise under the car then. It sounds and feels like it is coming from directly under the driver's feet. The car is also squealing a bit when the brakes are depressed which I assumed was the squealers starting, but the mechanic claims brakes are fine and did not seem interested in diagnosing the sound. The noise could be totally unrelated but thought I'd include all the details just in case.

Accordingly to mechanics that have seen the vehicle about 3-months ago, before this particular issue was really noticeable, the brakes and the transmission are fine. I also recently had the fuel pump replaced, and I am taking it in today to ensure the mechanics that checked the brakes put the tire back on correctly. I have had wheel bearing issues with my other Buicks, but this seems different.

Is there an arm or other device that controls depression and release for both the brake pedal and accelerator pedal that could cause a noise like this? Or any other ideas?