lack of power while driving with pedal to floor will not go any faster
lack of power while driving on 2006 Chevrolet Uplander
Could be so many things it would be foolish to speculate without being able to do some basic diagnostic tests. Has the Check Engine/Service Engine Soon light been on? If so codes will be stored in the computer of your car that will indicate where the problem is, (you need a scan tool to retrieve the codes). You could have a lack of fuel pressure or a restricted catalytic converter hard to say.