I've replaced spark plugs, tps, iac and cleaned the mass air flow sensor and throttle body and the sensor that reads the intake pressure, and both oxygen sensor. The cat has been gutted out for about 6 or 7 years. 

I still get a random misfire on all 4 cylinders. I've replaced the coils too but that didn't fix the problem. The problem happens every morning when the car is cold, and I t stalls when making a complete stop. After it is warmed up it runs like a champ.