97 Ranger 4 cyl - Check engine light came on - 4 codes - possible vacuum leak?

[Bill_M]

Hi

1997 Ford Ranger Supercab - 4 cylinder - 5 speed manual transmission - No AC - No modificatione

Check Engine light came on and engine is now running rough and is misfiring, especially at lower speeds/RPMs (seems to run better at 55mph and above). Muffler/exhaust pipe is rattling much more than normal.

Parts store diagnosis reported following codes (each code shows up twice)

4 codes are reported (in following order):
P0141 Oxygen Sensor Heater Circuit Bank 1 Sensor 2
P0402 Exhaust Gas Recirculation Flow (Excessive Detected?)
P0303 Cylinder 3 Misfire Detected
P0171 Bank 1 System Too Lean

Part store recommend I replaced the 02 sensor which I did and seemed to run a little better for a day or so but once again running as described above. Returned to parts store and tester shows same 4 codes (twice).

Do I need to reset the computer after replacing the 02 sensor?

I hope this issue won't destroy the catalytic converter.

Rather than chasing codes I suspect a vacuum leak. Anyone aware of a troubleshooter guide for such an issue or other recommends? Thanks.

 

[Tedybear]

Hi

1997 Ford Ranger Supercab - 4 cylinder - 5 speed manual transmission - No AC - No modificatione

Check Engine light came on and engine is now running rough and is misfiring, especially at lower speeds/RPMs (seems to run better at 55mph and above). Muffler/exhaust pipe is rattling much more than normal.

Parts store diagnosis reported following codes (each code shows up twice)

4 codes are reported (in following order):
P0141 Oxygen Sensor Heater Circuit Bank 1 Sensor 2
P0402 Exhaust Gas Recirculation Flow (Excessive Detected?)
P0303 Cylinder 3 Misfire Detected
P0171 Bank 1 System Too Lean

Part store recommend I replaced the 02 sensor which I did and seemed to run a little better for a day or so but once again running as described above. Returned to parts store and tester shows same 4 codes (twice).

Do I need to reset the computer after replacing the 02 sensor?

I hope this issue won't destroy the catalytic converter.

Rather than chasing codes I suspect a vacuum leak. Anyone aware of a troubleshooter guide for such an issue or other recommends? Thanks.

I would actually start with the EGR issue. Could be a vacuum leak, but if the EGR is stuck open, you'll have exhaust gas recirculated into the system and it will cause the engine to run poorly at idle and low speeds.

S-

 

[Bill_M]

Thank you.

The truck has been very good to me with basic maintenance (117k miles). About time I learn more about the under the hood emissions systems.

Will investigate EGR system tonight and post follow-up.

 

[holyford86]

It is unlikely that the egr valve itself is bad, it is more likely a DPFE or EVR issue.

Sent from my SM-G900P using Tapatalk