Poor acceleration after coming to a stop and then take off. After engine warms up.

If the engine runs well and seems to have power, but the vehicle is sluggish or has poor acceleration, it's possible that the transmission is not shifting down for acceleration or may be starting off in a high gear because the computer has detected a malfunction and has put the transmission in a fail-safe "limp-in" mode to get you home or to a shop. Usually, there would be a warning light on if the transmission was in limp-in, I recommend you take it to a transmission shop or a GM specialist for diagnosis. If you want to find a specialist, here's a directory link for you: https://repairpal.com/pontiac-repair-in-washington-district-of-columbia