Rough idle, low RPM, bucking on acceleration 2000 O2 sensor help

[ChestnutHill]

I’ve owned my 2000 Sport 4.0 5speed (202k miles) for about 3 years now. It’s always run like a clock until yesterday- RPMs dropped, started bucking on acceleration, etc. After some research I figured it was the Throttle Positioning Sensor, so replaced it this morning and it seems marginally better (does the TPS have to relearn?) but I’m still having the same symptoms.

Bought a scanner and I’m getting codes P0132, P0135, and P0141. I also have what look like two new O2 sensors not hooked up to anything (pic)? They weren’t plugged in before and it was running fine… I’m stumped. Help!

 

[ChestnutHill]

Closing the loop on my post above now that I’ve resolved the issue. Hoping this is helpful for anyone with an early 2000 model year, which only came with two O2 sensors. Maybe obvious to others?… Although given the amount of research I did, there isn’t much out there on how unique the 2000’s are…

Per my original post I have two new-looking O2 sensors that don’t connect to anything (circled in yellow)- My best guess is that the exhaust header was replaced at some point with a non-2000 MY part, which seems likely. The O2 sensor locations were then “plugged” with the sensors… hence my original confusion.

The O2 sensors on the MY 2000 are located much further back in the system. The “upstream” sensor (NGK 23122) is just forward of the transmission skid plate near/along the passenger side frame rail.

Once located I was able to find a replacement sensor (this particular one is difficult to find…). The Jeep fired up and is running like a top again without any idle, low RPM, or acceleration issues. All fixed.

Hope this helps other 2000 MY owners in the future searching for O2 sensor help.

 

[reddvltj]

Closing the loop on my post above now that I’ve resolved the issue. Hoping this is helpful for anyone with an early 2000 model year, which only came with two O2 sensors. Maybe obvious to others?… Although given the amount of research I did, there isn’t much out there on how unique the 2000’s are…

Per my original post I have two new-looking O2 sensors that don’t connect to anything (circled in yellow)- My best guess is that the exhaust header was replaced at some point with a non-2000 MY part, which seems likely. The O2 sensor locations were then “plugged” with the sensors… hence my original confusion.

The O2 sensors on the MY 2000 are located much further back in the system. The “upstream” sensor (NGK 23122) is just forward of the transmission skid plate near/along the passenger side frame rail.

Once located I was able to find a replacement sensor (this particular one is difficult to find…). The Jeep fired up and is running like a top again without any idle, low RPM, or acceleration issues. All fixed.

Hope this helps other 2000 MY owners in the future searching for O2 sensor help.

The 2000 MY 4.9l came in 2 iterations, Federal emissions and CA emissions. Both came with a split style header that runs into a Y. The CA addopted the higher emissions standard 4 sensor system with dual precats just after the header, while the Federal emissions kept the 1999 2 sensor O2 set up. They changed the location of the sensors for the CA emissions to 2 sensors in the maniifold, and 2 directly after the precats. The Fed kept the the sensors down in front of and after the cat.