I got a 2010 mercedes benz c300 the check egine came on the code is p2422 everytime time i put gas it wont start i gotta press the gas peddle couple times and it starts but i gotta keep the peddle down because it turns off but thats only when i out gas i been reading its something about the valve on the charcoal canister but i dont know can someone plz help me i know if i take it to the dealer its gonna be alot of money. Thank you

Usually a failed evap purge valve that sticks open, causing a vapor lock when you refuel. Change it and see if it improves.