If it's a clean steady engine vaccum probably not. But if it shares a fitting with a brake booster then every time you hit the brakes it drops to fill booster. When it drops the MAP thinks there's a load on engine and adds fuel. Like above in a fitting on number eight intake runner pulsed with intake stroke of that cylinder.

Every GM EFI vehicle I have seen is a designated MAP sensor vacuum port for a true uninterupted intake manifold vacuum source. So GM thought it mattered.