A while back, I took my APS M4 in order to downgrade the spring and add metal bushings. I haven't gotten it to function the same since. It's been reshimmed, regreased, and the AOE has been corrected. The gearbox constantly locks up when the gun is fully put together and it has an incredibly slow firing rate( like the battery is dying) on a full charged 8.4v when the gearbox is alone. The wiring does have a few kinks in it as well. Should I rewire it?