2002 Ford Ranger 4.0L with P0602 and O2 Sensor Codes 136, 142, 171, 174 - Too Lean Condition
I have a 2002 Ford Ranger 4.0L engine displaying PCM fault code P0602, along with oxygen sensor codes 136, 142, 171, and 174 indicating a lean mixture condition. The vehicle starts easily and accelerates well, but the idle is rough when the engine is warm. I recently cleaned the intake valve to rule out sticking components, but the symptoms persist. Any recommendations for diagnosing or resolving these codes?
Do you have access to a scan tool to monitor real-time fuel trims? Also, please confirm whether the O2 sensor codes 136 and 142 are still present and active in your vehicle's diagnostic system.