Emboar's weak to Psychic, Flying, Water and Ground.
Rotom-W is only weak to Grass, immune to Ground, and has a Flying and Water resistance. It can also deal with them with a STAB move.
Rotom-W @ Leftovers
EVs: 252 HP, 76 Sp. Atk, 180 Sp. Def
- Volt Switch
- Hydro Pump
- Pain Split/ Thunderbolt