What causes engine surges under 60mph?

Engine surges under 60 mph can be caused by several factors, including fuel delivery issues like a clogged fuel filter or failing fuel pump, which disrupt the flow of fuel to the engine. Ignition system problems, such as faulty spark plugs or ignition coils, can also lead to inconsistent engine performance. Additionally, issues with the air intake system, like a dirty air filter or malfunctioning mass airflow sensor, can affect the air-fuel mixture, resulting in surging. Lastly, transmission problems or improper gear shifting can contribute to erratic engine behavior at lower speeds.