Bicycle Mechanics - That squeak that won't go away.

I have this friction squeak and I cant figure out what its from. Its when Im pedaling. It happens as im pushing down and forward, goes away after it hits the bottom of the arch, then starts again. Happens on both sides so its a constant pulsing squeak. Ive properly lubricated the pedal bearings and other parts of the whole crank setup that would benefit from such things, and it stopped for awhile. Then it started again twenty four hours later. I cant seem to isolate the problem because it only happens when my weight is on it, so I can't flip the thing over and figure it out. Any clue what this can be?

Does the squeak remain when you are standing or only seated or both? I had a similar noise that I was certain was in the bottom bracket or crank but found it only occured when I was seated and pushing with some force. Light spinning didn't produce it and standing made it go away too. The problem was really in the seatpost and/or seatpost clamp that I hadn't greased adequately.

If it really is in the crank area, remove the crank arms and bottom bracket, HEAVILY lube the bottom bracket and bb shell threads and torque them to spec.

Squeaks and other noises in a bike can be infuriating since their source is not always as obvious at it first seems.

check your crank arms where they connect to the BB , they ( or one of them is ) lose . tight the bolts. You can also put a little grease on the BB axle and put on the arm. Put the arms at 3 & 9 push & pull on them , if they are lose they will move. your BB may also be lose and need adjustment.

Yeah its most certainly on the lower end; Ive had seat squeak issues before on another bike and cleared it up. This only happens when im putting pressure as Im pedaling, it stops when Im backpedaling/coasting, standing or sitting.