I scanned my car at WOT recently and my O2s read 985mv and my
injectors(stock 24#) read 104% duty cycle all the way to the
6700rpm shift. What is my problem here, too small of injectors,regulator,fuel pump or just tuning issues? BTW, my fuel system is all stock.

 

Your car is probably running rich and the (calculated) DC is off due to it. You could try leaning out the WOT AFR some... of course this would be easier and more accurate if you had access to a wideband dyno.... plus you're also maxing out those stock injectors. Try some 30# SVOs.

 

I have been planing to get some 30# injectors, but I am wondering if leaning out the fuel with LT1 edit will bring down my
high duty cycle very much.

 

Are you using the stock WOT AFR table? In my experience, I've had to lean out most 306 cams even with stock injectors.

 

I dont think it is the stock table. I have had three different tuners
(2 popular ones) and my car has always ran this rich with the cam.
The last tuner that looked at it,said I need bigger injectors and
more afr tuning. I am just wondering if just the afr tuning alone would be more of a help rather than injectors. I have seen alot of cc306 cars run good on stock injectors as well as 30#.

 

So, am I at a point where I absolutely need injectors or can it be
the afr tunning maxing the duty cycle?