Hi, I was driving around 300 miles in 93*f heat and the engine developed this hesitation/sluggishness around 1800-3000rpm. Got a check engine light for o2 sensor, no fault code in particular, which I have suspected since the pre cat o2 sensor had to be changed 2 years ago. The next day I have installed a used pre cat O2 sensor and cleared the code and it fixed the issue i thought.
After further investigation, O2 pre cat and post cat sensor was reading correct voltages, I then wanted to check the MAF sensor since it is a common suspect, but my car only has an intake temperature sensor and a map sensor. Cleaned the Intake sensor, and was reading correct air temp. I have then checked my values during load with an OBD2, and the thing that stood out was the air fuel ratio, climbing from a steady 14.6 into the 29's, Map sensor also reading questionable readings. Suspecting different things firstly a bad MAP sensor/o2 sensor/ catalytic converter/ air inlet temp sensor.
After further investigation, O2 pre cat and post cat sensor was reading correct voltages, I then wanted to check the MAF sensor since it is a common suspect, but my car only has an intake temperature sensor and a map sensor. Cleaned the Intake sensor, and was reading correct air temp. I have then checked my values during load with an OBD2, and the thing that stood out was the air fuel ratio, climbing from a steady 14.6 into the 29's, Map sensor also reading questionable readings. Suspecting different things firstly a bad MAP sensor/o2 sensor/ catalytic converter/ air inlet temp sensor.
Jul 30, 2025 at 10:23 AM
