I'm not sure where to post this since there are so many threads regarding "rough idle," but maybe my point will get around, if it hasn't already.
I'm the original owner of an '06 Pathfinder. In April of 2014, at 105,000 miles, I had the timing chain, guides replaced for noise.
Fast-forward to 2019, started to feel a rough idle. Wondered if it had something to do with worsened gas mileage. I lived with it.
In 2021, the check engine light throws the code for CAT converter. That code, we all know, is not very specific and can mean many problems. I had the bank-one CAT converter replaced.
The code returned. I replaced the bank-one-after-CAT O2 sensor.
The code returned. I replaced the before-CAT O2 sensor.
The code returned. I checked the exhaust for leaks and found one at the CAT-exhaust joint. I replaced the gasket there, but the leak persisted. I took it to a shop and it was found to have a pinhole in the exhaust near the gasket. Welded it.
The code returned. I replaced the MAF sensor and cleaned the throttle, which looked fine.
The code returned. Because the low idle sometimes causes the oil pressure gauge to dip, I changed the oil out for 10-30 in hopes of tightening things up.
The code has not returned!
But the idle is still rough. I love this rig but for this stupid rough idle. I searched the net for answers, aggressively at first, then half-heartedly. Then, I found this:
https://www.motor.com/wp-content/upload ... E_0116.pdf
I think this is my problem. I don't know that Nissan replaced the gasket material in the rear timing cover. Probably not, since it's not necessary to do so to replace the chains.
My dilemma is fixing this (or attempting it.) It's a 20-30 hour job for me or probably 3 to 4 grand. I have upgraded this 4x4 from grocery getter to off-roader. I still have more upgrades in mind. This problem makes thinking of buying an FJ more palatable.