Engine bogging down

I have a 1999 Buick Century (3.1 engine) with 89,000 miles. When you start from a dead stop the engine bogs down and the car creeps forward. Suddenly the car takes off and is fine until the next stop. It only happens from a stop after the engine has reached operating temperature. It does not happen when cornering or when accelerating while you are moving. The dealer has replaced the fuel pressure regulator, cleaned the injectors twice and replaced the mass air flow sensor. No codes show when scanned. Any solutions?

Could the calipers on the brakes be hanging up, or the brakes not releasing for some reason? When it happens, shift to neutral and try revving the engine to see if it bogs down. Also, on a clear stretch of road with not traffic, try coasting to a stop without applying the brakes, then accelerate. If the car doesn’t bog down, this would be reason to suspect the brakes.

The dealer checked the brakes last week and they were fine. They were replaced last summer

Used to happen in the old days if too much cold air was getting into the intake. Loose ductwork between the injector body and the heat box can do it. Hope it’s that easy. The tube from the exhaust manifold and the heat box (air filter box) may be broken or disconnected. It would be nice if the cause were simple.

Dealer checked the ductwork today and said it was fine.