Engin error light code indicates engine running lean. on 2002 Mazda Protege

Where do I find what should be checked and in what order. Also, what would the cost range be for repair shop fixing problem?

1 answer
Here's some info on the p0174 and p0171 codes that normally occur when the engine is running lean: http://repairpal.com/OBD-II-Code-P0171-and-P0174
A shop will likely charge about an hour of labor to diagnose this, maybe less but maybe more, depending on the difficulty in finding the problem.