P0132 P0171

Copy and paste from another XJ forum

Last night my CEL came on and went to scan the code. P0132 came up. Bank one sensor 1 upstream O2 sensor. I replaced that o2 sensor back in May

This morning, I noticed a rough idle along with the present code. I cleared the code to see if it would come back. It did not for a bit of driving but I still had a rough idle. I pulled the Throttle body out and the upstream o2 sensor. The TB was not dirty and the IAC was somewhat coated. I cleaned both
The O2 sensor was covered in carbon. I cleaned that as well. During the whole process I saw that the pcv tube connecting to the intake was not completely in. It's a newish hose with a hose clamp. I retighen that

Now after some driving, I dealt with some bucking, sorta the same thing that happened before replacing my 02 sensor back in May. The CEL came back on and it's P0171- system too lean.

I ordered a new o2 sensor but it won't be here till Tuesday. At this point im sorta afraid that an o2 sensor isn't my problem.

What should I all look for besides leaking vac lines?

What brand O2 sensor did you buy?

In the meantime, check the harness going to the O2 sensor.

I replaced the O2 sensors last spring with NGT sensors. The one that's coming Tuesday is Bosch. Napa can't guarantee a NGT coming in any time soon.

I checked the harness and it looked fine

NGT? Do you mean NGK or NTK?

What year is it?

Did you only check the harness visually? You should test the resistance on heater circuit on the sensor and test for voltage at the engine harness.

I meant NTK

It's a 2000 4.0 with federal emissions

I did check the wires on the sensor and didn't see any bad wires. Had the Jeep in start position to check for voltage/resistance. Didn't hit me to have the vehicle running to check for voltage and resistance

While the Jeep was on I did look for any obvious vacuum leaks. Could not spot such leaks