Wait a second, you removed the rrfpr? So basically you are boosting without increasing fuel? If you use stock injectors, you need the rrfpr to raise the fuel pressure relative to boost. with larger injectors you dont need an rrfpr but you need a way to control the injectors. I think you need to do ALOT of reading over on rs25.com
And no, a GM map sensor is for tuning purposes only. You still need the factory sensor hooked up and clamped.