the problem is in the emission system and replaceing the engine will not fix it . and insted of replaceing O2 sensors just becase of the code is throwen is a wast of money anter the new set of O2s were installed the shop should have gotten a clue as honda doesn't make O2 sensors NTK,NGK or Bosche does . as long as it has the OEM plug they work the same! if we get a O2 code the customer gets a option to have just replace the sensor or have it diagnosed the sensor read through the scanner as the computer would see it and the sensor itself is tested also. then is replaced if needed but if the customer doesn't want to pay the extra $$$ and just wants it replaced without us doing the complete diagnostic then they are on their own if the same code comes back up again!