Hard starting and running rough?

So, whenever I start the car, it idles very rough and the engine stalls. No 'Check Engine Light' is present at any time. I need to feather or depress the gas pedal to keep it from stalling. If I get the engine to somewhat warm up, then it idles very rough. The thing that happened was that I didn’t change the air filter for a while. One day I came from work, and it was idling rough. I pulled the air filter and the filter had disintegrated so some particles from the air filter went inside the intake manifold. It had a code which was the air mass flow sensor, and I replaced it but it’s still doing the same thing. It was running fine before this happened.