Yours probably need to be taken apart and cleaned. The axle acts as the cone and is likely pitted. If so it's best to replace the pedals.
I run shimano SPD pedals and evey 2500 to 5000 miles pull the cartridge out and clean the housing. I then fill it with grease and install the cartridge pushing out the old grease in the cartridge.
On the MKS and other pedals you can remove the cap and push the grease through until clean grease comes out of the crank side.