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P0171 and P0174 Fault Codes on 1998 Mazda B4000 - Engine Hesitation and Rough Idle

Model: 98 mazda b4000 Fault Code: P0171 Posted: 2008-12-05 16:26

I took my 1998 Mazda B4000 to a garage, where they replaced the mass airflow sensor and fuel filter. Despite these repairs, the vehicle continues to show P0171 and P0174 diagnostic trouble codes. The engine also hesitates during acceleration and runs with a rough idle. Any suggestions on potential causes or further troubleshooting steps?

Related fault codes

P0171P0174

Comments (2)

Anonymous 2008-12-05 18:17

A vacuum leak is likely the root cause, especially since the 4.0L engine in your Mazda B4000 shares similarities with the Ford 4.0L. The most common source of such leaks is the PCV (Positive Crankcase Ventilation) hose.

Anonymous 2008-12-05 20:03

Vacuum leaks from the upper intake manifold gasket are also very common in this model and can directly contribute to P0171 and P0174 codes, as well as rough idle and hesitation during acceleration.