Need a little help with a lean condition. Recently installed a top end kit on my fox. The car is running lean at idle according to the wideband. In the area 17-18. I installed 24lb injectors, C&L maf calibrated for 24lb injectors. New fuel filter and 255lph fuel pump. I currently have the fuel pressure regulator maxed out to 55-60 psi. If I crank down the pressure to 39-40. The car runs rough & the wideband goes so lean it doesn't give an AFR. Any suggestions or possible causes?