I agree with @hahahaka's answer..some suggestions then can make the e4 easier:
A gyarados with this moveset: earthquake, crunch, ice fang, dragon dance
If you keep using dragon dance at the beginning, you can sweep most of the pokemon
A fast gengar with: thunderbolt, giga drain, sludge bomb, and shadow ball
A strong clefable with moonblast, psychic, soft boiled, and toxic could also be helpful
There is also a lending system out now, so you could always borrow a high level pokemon to get through the e4!
Hope this helps!