P2187, P0134, P0455 Fault Diagnosis on 2007 Mazda5 with 4-Speed Automatic Transmission and 50,000 Miles
My 2007 Mazda5 (4-speed automatic, 50,000 miles) is throwing diagnostic trouble codes P2187, P0130, and P0455. The vehicle exhibits a slightly rough idle and once stalled at a stop—though power remains otherwise normal. I've already verified the gas cap is secure. Given these symptoms, I suspect the purge valve may be faulty. However, I'm seeking input on a reliable troubleshooting sequence or decision tree to follow. Any insights or guidance would be greatly appreciated.
Codes P2187 and P0134 relate to 'System Too Lean at Idle (Bank 1)' and 'O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)', respectively. Before replacing the oxygen sensor, thoroughly inspect the wiring harness and electrical connections—ensure they are secure and free from corrosion. If the sensor is faulty, it's recommended to replace it with an OEM part from the dealership rather than aftermarket options. Additionally, check for any vacuum leaks, as these can contribute to lean conditions. For P0455 (Evaporative Emission System Leak Detected), inspect all EVAP system hoses for cracks, tears, or disconnections. Addressing these components systematically should resolve the issue. Good luck and please update with your findings.