I have a Nissan 2001 Pathfinder I bought new in 2001, but it was actually manufactured in early 2000. Currently only 61K actual miles. I have read in the past that this new model engine, 3.6L, has a history of MAF and coil problems (one coil on each cylinder). So far, the 1, 2, 5, and 6 coils have failed between 42K and 61K miles. The MAF failed at 59K miles. Fortunately, I have an engine analyzer that identified the coil failures. Unfortunately, for the first 3 failures, I bought after market coils that seemed to really screw up the ignition system and resulted in many other error messages. These finally cleared up when I replaced the after market 1, 2, an 5 coils with OEM parts. The MAF failed such that it wouldn't pass the Denver area emission tests. I took it to a shop that identified the problem as the cats. The replacement cats were really expensive, so they welded in new cats for $1000. This didn't fix the problem. I took it to the state emission testing lab that told me the problem was the MAF. I took it back to the shop, they were kind enough to reverse the cat charge and replaced the MAF for $800. They used an after market (probably remanufactured) MAF that lasted less than 2000 miles. I replaced it with an OEM MAF myself for $200. So far so good, but only a few miles.

My questions are:
1. How common are these failures?
2. Is it because I bought a VERY early 2001 without the bugs worked out?
3. Should I replace # 3 & 4 coils now?
4. Has Nissan fixed the coil problems so the new coils will last, or is it a general ignition problem causing the failures?
5. Has Nissan fixed the MAF problems?
6. Do I have any recourse with Nissan?

I really like the SUV when I runs OK (250 HP with manual 5 speed), but these problems are becoming very annoying.

Rick

1.) Yes this unfortunately a common issue, typically associated with your ground wires causing more resistance than normal. Try adding a new ground from the block to the battery, 10-12ga wire should do.
2.) No, this happened throughout all the years of this body style.
3.) I wouldn't replace them unless they're failed.
4.) you have to consider age more than mileage. Your vehicle is 13 years old, It will have problems, especially electrical component degradation. The code you got using aftermarket coils is common, ignition signal 1 usually. The new OEM coils are an updated part.
5.) The "MAF Problem" was more the element getting dirty and over heating than an actual issue. They make a cleaner you should use on the MAF every time you change the filter.
6.) no, 13 year old vehicle, its far out of legal recourse.