Mazda Tribute Forum : “what would make the accleration slow down?”

How many miles are on it? Could be the fuel filter or air filter.

Have you had any other services performed lately that could have caused something to go wrong?  You might have a clogged fuel system.  Have the fuel filter replaced and run fuel system cleaner through the tank.  Also, check the exhaust system and make sure that nothing caused the piping to collapse.