I got the same error code on a 98 Ford Explorer. I have searched online, and the 1st cheapest step is to clean the mass air flow sensor. If that does not do the trick, get a new mass air flow sensor, then oxygen or 02 sensors could be bad. P0171: fuel system lean bank 1
Trouble code P0171 means: Fuel System Lean (Bank 1)
Trouble code P0171 means: Fuel System Lean (Bank 1)
Trouble code P0171 means: Fuel System Lean (Bank 1)
Trouble code P0513 means:Incorrect immobilizer key
Trouble code P1391 means: Intermittent loss of CMP or CKP
Trouble code P0171 means System too lean (bank 1)
Trouble code P0401 means:Exhaust gas recirculation flow insufficient detected
Trouble code P0171 means:System too lean (Bank 1)
Trouble code P0171 means: System too lean (Bank 1)
Trouble code P0171 means:System too lean (Bank 1)
Trouble code P0441 means:Evaporative emission control system incorrect purge flow
Trouble Code P1294 means:Target idle not reached