I am running extremely lean on a stock sr set up my aem wide band gauge is maxed out at idle and when cruising the gauge reads in the 16s.. I am running a walbro 255 fuel pump and getting 40 psi fuel pressure. I have already checked timing cleaned maf checked voltage coming off the maf and smoke checked for vacuum leaks all injectors are firing. The problem is causing me to stall out when i shift into neutral. Could the sr o2 sensor be bad?