My car has recently been given me problems. When I am stopped at an intersection and then go sometimes the engine looses power then ruff idles and I can only go about 5 mph I turn the car off and on and it’s fine. When I press the gas peddle down pretty hard and it looses power and ruff idles . It also backfires sometimes. What could be the problem it is starting to get worse. \

It’s a 1995 C280