Sr running lean

[S13NismoStyle]

Hi, i just recently installed a aem uego wideband into my s13 blacktop sr. Its just about completely stock. I just have a full exhaust, z23 tt fuel filter and a fmic and im using a 180sx fuel pump. Ive been running it at about 10lbs with the stock t25 for the past couple of weeks with no problems really. But now, after installing the wideband i have noticed that my afr's have been running about 13.5-14.0 at wot. so i went and disconnected my mbc and was running vac straight to my wastegate. so now underfull boost it creeps to 8-9psi, but my afrs are still around 13.5 or so. I know this is way lean and im wondering what the possible causes could be. also my car is always running lean when crusing and not under boost. is this normal? i thought that the factory tune would be rich if anything. thanks for the help.