So I'm just looking for other suggestions on what could cause this, motor is a LS running on a stock LS ECU.. the car bogs to the point of cutting off anytime its under 1500-2000 rpm's I have checked mechanical timing many times and seems to be dead on.. however when I advanced the ignition timing it cleared up noticeably but still wants to bog and sputter.. when taking off so at this point when I have time to work on the car(I work 3 jobs) I planned on checking the adjustment on the valves ... that is the only thing I can think of at the moment... Does anyone think maybe I'm having a injector malfunction?? I also noticed at low rpm and wot it clears up ... any replies would be great and I will update as well thanks HT!!!

PS only CEL is for the o2