1996 Chevy Impala OBD TEST RESULTS

Engine Mechanical problem
1996 Chevy Impala V8 Wheel Drive Type unknown Automatic 110000 miles
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I failed my OBD test and three codes popped up. I was wondering the cheapest way i can fix this problem, what do the codes mean and caused them?

Codes Description
P0171 System to Lean (BANK 1)
P0174 System to Lean (BANK 2)
P1661 Manufacturer Specific Code




Thanks.