map sensor causing rich cond. on 2000?

hello all,
i have a 2000 blazer here and have a couple questions that maybe some gm techs will help. will a faulty map sensor cause a bank1 and bank 2 too rich faults on a mass air flown vehicle. my map sesor is reading 10hg. i dont have a vacuum gauge readily availible to see acual vacuum, but i know its not at 10hg by the way its running and idling. i always thought that on a mass air flown sysytem the map sensor was used as a dignostic tool for the pcm. is this not the case on this blazer. i already changed the leaky injector in the cfi unit and it helped but im still running rich, more on bank2 then bank1. whaddyathink?
thanks
kevin

Is the O2 sensors saying it is running to rich?

Have you done a tuneup with plugs cap wires, air filter etc.....

yes, the sensors are indicating that it is running a bit rich. did not do a tune up , has 40k on the odometer. jsut confused on why the map sensor reads 10hg of vacuum.
thanks