It is possible that a clogged catalytic converter could cause your 2006 Quest to accelerate slowly. Over time, the converter can become clogged with debris, which can restrict the flow of exhaust gases and make it harder for the engine to run efficiently.
When the catalytic converter is clogged, it can cause a number of symptoms, including a decrease in engine performance, reduced fuel efficiency, and difficulty accelerating.
In addition to a clogged catalytic converter, there could be other issues that are causing your vehicle to accelerate slowly. Some other potential causes of slow acceleration include a faulty oxygen sensor, a clogged air filter, a malfunctioning mass airflow sensor, or a problem with the fuel system.