2011 Nissan Altima

I had put bad fuel in my car and it messed up the fuel pump.  I took the car to a mechanic and he replaced the fuel pump; he also said he had to replace the mass air sensor.  My car still was missing; He replaced the injectors and spark plugs and still my car is missing.  I don’t know what else to do, I already am in debt $2,000.00 and the car isn’t any better then when I took it in.