My car has been choking and sputtering for the last 2 weeks,

I have put in 2 bottles of fuel injector cleaner with a full tank of gas,in the last week however it is still doing the same thing. I checked all the fluid levels and added some oil{it was half down}.It is a 4cylander and it sputters when i step on the gas, could you please help me. Thank you Jo-Ann