If you don't run a LiPo battery already, get one. A 7.4 will work in any gun, 11.1's are my general go-to. Check your motor height to see if it is causing too much pressure on the gears to the point of nigh-failure, check the shimming of the gears, finally, check that you aren't using a disgustingly strong spring in the gun (when I first started the sport and didn't know anything, I bought an m160 spring, paid the store I bought the gun and spring from to install it for me, and played with a g&g p90 running WAAAAAAY too hot for any field. Wish someone would have approached me back then and taught me the basics of upgrades and parts when I was shiny-eyed and new lol), and finally check the battery you are using to see if it's on its way out and not holding a charge properly.
mk43, ump.45, p90, barret, m14, g33, k98, m4 tac, m4 swat, mp5 navy, vsr10, p226, m9.