Like others have said, you can get your own fuel injector cleaner from any auto store for $7 - $8. But if the car is running well and not sucking down gas then don’t even bother. 43k is pretty low mileage to have to be worrying about this. Presumably you’re servicing your car at the dealership and they always try to upsell customers on useless stuff like that. You should find an independent mechanic to work on your car either that or just turn them down on that stupidity.