Runs poorly in closed loop

[Viper588]

Idles and drives great when cold and in open loop but as soon as closed loop it goes lean (O2 voltage sits at .0 and stft jump to 25%) and starts to run like crap . I just discovered that if i block off 3/4 of the intake the car will idle normally. (There are no vacuum leaks, fuel filter replaced, tried diff maf, changed O2, new CTS, new IAC) My MAF shows that at the current idle(900-1000 rpm) its showing airflow of about .8-1.1 Lbs/min. I cant find any information about whether this is a normal amount. The only thread i found was anohter guy seeing about half as much airflow at the same rpm but he has the 2.0 4g63 where i have the 2.4 4g64 so i assume air flow on mine should be higher? Any help or opinions would be appreciated! Thank you!