My van started sputtering after I brake and does not respond well once I speedup on 1999 Plymouth Grand Voyager

but once I get up to 40 mph it drives fine. Also when I turn on the ac or defrost, it starts sputtering again. Can you tell me whats going on?

Asked by for the 1999 Plymouth Grand Voyager
do you have a service eng soon light on? if so get scanned at auto zone and post codes so we can adv