2000 Pontiac Bonneville Repair Question
ok, first i would look at the plugs and wires. it sounds like it is missfiring with the sputtering.
the black smoke could be from the missfire or it could be from a failed fuel pressure regulator sucking raw fuel into the motor.
the bog could be fuel pressure related or a bad supercharger.
all these could be the reason but you need help from a shop that can touch it and feel the issue and give you a bid.
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