When I press on pedal, intermittent loss of power
This sounds like there's a problem with your rear hub's freehub body (assuming you're running a cassette). The pawls get messed up sometimes and cause a jump when you're pedaling. If this is the case, you can try to replace the freehub body, which requires a bit of work. You basically have to take the axle out of the hub and get a 10mm wrench down there (most common method).