If your vehicle is showing engine hesitates, bogs down, or stumbles when pressing the gas pedal, here are the most likely causes and the parts you'll need to fix each one.
The MAF sensor measures the amount of air entering the engine so the computer can add the right amount of fuel. If it is dirty, it underestimates the airflow during sudden acceleration, causing a lean mixture and a hesitation or stumble.
A loose intake boot, disconnected vacuum line, or failing gasket allows unmeasured air into the engine, leaning out the mixture. This is a very common installation error after checking the air filter or performing engine work where a hose is accidentally left unplugged.
Under heavy engine load (like accelerating), it is physically harder for the spark to jump the gap. Worn spark plugs or weak ignition coils will misfire under this load, which feels like a sharp stumble, jerk, or hesitation.
Carbon buildup in the throttle body can restrict initial airflow, or a worn 'dead spot' in the Throttle Position Sensor can delay the computer's response to your foot pressing the pedal, causing a momentary bog.
When you press the gas pedal, the engine demands a sudden surge of fuel. A clogged fuel filter or a weak fuel pump cannot deliver the volume or pressure fast enough, causing the engine to starve and bog down.
If the exhaust system is severely restricted, the engine cannot breathe out. It may idle perfectly fine, but when you try to accelerate, the exhaust backpressure chokes the engine, causing a severe bog or total lack of power.