zroth1992

For the past few months my 1998 mustang v6 3.8 liter has been running the codes po172 and po175 as running rich. The iat sensor reads correctly, the mass air flow sensor has been replaced 3 times, the fuel filter has been changed, there has been a tune up done, the fuel pressure regulator was changed, the vacuums and manifold have been checked for leaks, and the o2 sensors have been reading correctly. The car runs strong occaisoinally, but usually runs weak with soft bucking. When idling the cars short and long term fuel trims are in the negative and when at 2500-3000 rpms, the long term trims are at -20/-25 and the short term fuel trims are at 0/-8. What could still be wrong with the car? The mass airflow sensors were bought from autozone, not ford dealer.