Angkor

Hi folks,

I actually started asking questions about this last year and I've had great suggestions by members on this forum. I tried a few things but the problem won't go away. It seems to be getting worse. I'd greatly appreciate some troubleshooting suggestions again.

At the beginning of last summer, I started getting what seemed at 1st like a click in the pedals. It progressed into more of an inaudible vibration.
-I can best describe it as a short, deep grating type of vibration that I feel in my feet through the pedals (it sometimes feel as if the whole crankset moves slightly, but that could be just an impression). «Krrt.... krrt... krrt krrt...... krrt.........». Again, not a sound but a vibration.
-It's not regular (for example not at every cycle or always at the same spot in the cycle).
-It'll come from the right or left pedal at random, sometimes through both.
-It's quite constant.
-It only happens when I'm pedalling (not when free-wheeling).
-It doesn't matter whether I'm pushing softly or hard on the pedals.

At 1st I thought it was the pedals and I changed them. Then I had the crankset tightened. I finally had the whole internals changed yesterday : axis, bearings and casings (sorry if I don't know all the proper English terms).
And it still does it!!!

So at his point, I can only rule rule out that it comes from the pedals or crankset since they've been changed. Yet I distinctly feel it through the pedals...

Someone suggested that the vibration might actually come from the free-wheel and which would be transmitted to the pedals. But then, shouldn't I expect to also get it when not pedalling?
I also thought that it could come from my old derailleur : maybe grating of the chain on uneven gears? But it does it regardless of the gear I'm on.

Anyhow, I'm out of my depth with this. (I'm very mechanically-challenged so it doesn't take much...)

I have limited financial resources so I'd rather get it right before I bring it back into the shop again. So if you have any suggestion as to what to look for, I'd greatly appreciate.

Thanks in advance.

(PS- Sorry if I sometimes don't answer quickly. I remember there was a problem last year where I didn't always receive email notifications when people replied.)