I just finished installing my engine and I took my car out for a drive. I have noticed that when im just driving normal the car shifts and runs perfect. As soon as I stomp on the gas it kinda feels like it is shuttering a little. When sitting at a light on a fairly steep, while going up the hill, it started doing it again. I'm not sure if the tranny needs a rebuild or could it be the converter. I know nothing about the tranny since I bought the car with a rod knocking and this is the first time I have actually got to drive the car. Feels like it may have a shift kit. Also when I press the performance button I can't tell any difference.