Quad lifts off, hovers then sinks like it loses some power

I just rebuilt my quad with new motors and esc’s. I am having an issue. I take off, bring it up to a hovers and then 3-5 seconds later the quad starts to descend and no matter how much throttle I give it, it won’t lift. I calibrated the esc’s twice. Second time I used the passthrough all at once. First time was through esc calibrate button. My voltage is not dropping out, battery is fully charged. Mission planner connected with telemetry shows no errors or bad batt voltage. I could really use some help this has never happened to me.

Share data flash logs please.
Without logs it’ll be a guessing game :sweat_smile:

2019-05-04 13-35-01.bin (666.9 KB)

That is the only log I could load, it doesn’t show me taking off, but it wouldn’t even take off without tipping over. All motors spinning. When I have got it off the ground, it almost seems like a failsafe, where it slowly comes to the ground and I can’t gain altitude even going to full throttle

I figured out the issue. I checked the data flash logs and I didn’t see anything wrong. Heres what was happening, one of my brand new esc’s was bad. It was not allowing a motor to go full power and if it did, it cut it back shortly after. The quadcopter sensed a drop in the front left arm and compensated the other motors to maintain level flight by cutting their power as well. I replaced the bad esc and it hovers and flies fine. Thank you for your help anyway.

Although, the flash log does still give me an ekf error and ekf check error