Can biofuel-run vehicles still leave harmful emissions?

These vehicles are still cars and trucks and such. They still have engines that burn a hydrocarbon for fuel. So they still need lubricants and antifreeze, for example. Nothing has changed except the fuel used does not contribute to excess CO2 in the atmosphere, as long as the biomass is constantly replenished - ie: we keep growing the stuff that we turn into biofuel. But as far as everything else, they're still cars and trucks and buses, and I see no reason to believe we won't get the same pollution from them as we always have. The CO2 component of that pollution was always effectively unnoticeable to humans until we developed instruments to measure such things. CO2 itself is colorless and odorless, so we don't notice it without instruments, or until it has built up so much it starts poisoning living things, and then we just notice the effects, not the CO2.