If your vehicle is showing hesitation or stumbling when accelerating from a stop, here are the most likely causes and the parts you'll need to fix each one.
The MAF sensor measures air entering the engine. If it is dirty or failing, it miscalculates the sudden rush of air when the throttle opens, causing a lean hesitation. This is often caused by over-oiled aftermarket air filters or leaving the sensor unplugged after an air filter change.
Accelerating from a stop increases cylinder pressure, which makes it harder for the spark to jump the plug gap. Worn plugs or weak coils will misfire under this sudden load, feeling like a stumble or jerk. Incorrectly gapped plugs or loose coil connectors from a recent tune-up can also cause this.
Cracked hoses or failing intake gaskets allow unmetered air into the engine, leaning out the air-fuel mixture. This lean condition is most noticeable right off idle. Hoses are frequently left disconnected accidentally after unrelated engine repairs.
Carbon buildup in the throttle body can restrict initial airflow, or a worn TPS can develop 'dead spots' right off idle. This confuses the engine computer about how far your foot is on the pedal, causing a delay in acceleration.
The EGR valve recirculates exhaust gases to lower emissions, but it should be completely closed at idle. If carbon buildup causes it to stick open, it chokes the engine with exhaust gas when you try to accelerate from a stop.
When you accelerate, the engine suddenly demands a higher volume of fuel. A clogged fuel filter or a weak fuel pump may not be able to deliver fuel fast enough to match the incoming air, causing the engine to stumble.