how decent is my normal team, /vp/? Will I lose every match, or just most of them?

Slaking @ Leftovers
Ability: Truant
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Return
- Slack Off
- Rock Slide
- ThunderPunch

Porygon-Z @ Choice Specs
Ability: Adaptability
EVs: 248 HP / 252 SpA / 8 SpD
Modest Nature
- Tri Attack
- Ice Beam
- Thunderbolt
- Hidden Power [Fighting]
Meloetta @ Sitrus Berry
Ability: Serene Grace
EVs: 248 HP / 252 SpA / 8 SpD
Modest Nature
- Hyper Voice
- Psychic
- Focus Blast
- Thunder Wave

Ambipom @ Focus Sash
Ability: Technician
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Aerial Ace
- Fake Out
- Double Hit
- Power-Up Punch

Lopunny @ Lopunnite
Ability: Cute Charm
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Drain Punch
- Ice Punch
- Return
- Teeter Dance

Sawsbuck @ Choice Scarf
Ability: Chlorophyll
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Megahorn
- Grass Whistle
- Wild Charge
- Horn Leech