Hi folks, '05 TJ owner here, though I used to own a '97 TJ and an '01 XJ. Thank you so much for being such a good resource — I have used so many of these posts over the years to problem-solve issues that have come up.
My new (to me) '05 Sport just surpassed 150k miles. Over the course of the past two weeks, I replaced the PCV elbow valve (small oil leak), spark plugs (preventative - no issues), camshaft position and crankshaft sensors (CEL), and most recently installed a cold air intake. I did have to jerry-rig a grommet to get the 02 sensor to fit in the CAI, but it didn't look like there was an issue when looking at the voltage of the 02 sensors. It was running great until a P0421 code popped up, and I noticed a significant loss in power. Took it to a muffler shop and they confirmed that the cat is clogged and there are issues with one of the pre-cats.
Now, I want to make sure there are no underlying issues before I install the new exhaust system. Before the P0421 code, I did have one misfire code in cylinder 4 when I replaced the spark plugs, but I did not drive with the misfire. It was fixed right away. As far as the CEL light for the sensors, there is already a Crown OPDA installed, so I think it was just an issue with the aftermarket sensors.
What should I do to ensure that everything is okay before installing the new cats? What should I proactively replace at the same time?
My new (to me) '05 Sport just surpassed 150k miles. Over the course of the past two weeks, I replaced the PCV elbow valve (small oil leak), spark plugs (preventative - no issues), camshaft position and crankshaft sensors (CEL), and most recently installed a cold air intake. I did have to jerry-rig a grommet to get the 02 sensor to fit in the CAI, but it didn't look like there was an issue when looking at the voltage of the 02 sensors. It was running great until a P0421 code popped up, and I noticed a significant loss in power. Took it to a muffler shop and they confirmed that the cat is clogged and there are issues with one of the pre-cats.
Now, I want to make sure there are no underlying issues before I install the new exhaust system. Before the P0421 code, I did have one misfire code in cylinder 4 when I replaced the spark plugs, but I did not drive with the misfire. It was fixed right away. As far as the CEL light for the sensors, there is already a Crown OPDA installed, so I think it was just an issue with the aftermarket sensors.
What should I do to ensure that everything is okay before installing the new cats? What should I proactively replace at the same time?
