2000 Cadillac Catera MAF

Other Category problem
2000 Cadillac Catera V6 Wheel Drive Type unknown Automatic 40000 miles

The mechanic says that I must replace the MAF in my car. I don't believe him much, becuase he couldn't detect the failure of the crankshaft position sensor. I asked people about my problem and they helped to figure it out. Apparently, he did not check it with the diagnostic tool and now I am in doubt. So, I would like to ask what are the symptoms of the MAF failure. He also told me to replace something in the brakes touching it from outside of the wheel. I understand that there is a sensor that should indicate it, but he didn't tell anything about this sensor. Another question - he told me that I must replace front shocks, but I couldn't find front shocks on the parts sites, only rear shocks. Could you help me?
Thanks, Helen