I started this project several years ago with the purchase of high performance coils from Mission Ignition Systems. Not a well know name but a big player with Shelby American and NASA. What I have done may be an overkill in cost but the coils I purchased have already paid for themselves more twice over in the last 3yrs. The manufacturer had told me that the optimum performance efficiency of the coils I purchased is when they are run with a constant 16.5V input power. I was ready at the end of last year to purchase their Strike Force ignition voltage amplifier to complement the WeaponX coils I already have but after 3mo of backorder delays, a full refund and a complimentary prototype model they gave me for my trouble, which blew up shortly after I installed it, I went a different route for a voltage booster. Before the very well used and abused prototype blew out a couple of dielectric capacitors, I was able to scan some favorable fuel trim data real time so I was still encouraged to make this happen. Mission Ignition Systems do coils very well but I wasn't all that impressed with the way their voltage booster was built. Instead, I found JMS SparkMAX as a suitable alternative. I just finished installing it and I am very encouraged by my initial test drive. I'm expecting my Pathfinder to easily get 23+mpg in the coming days. For an old 2002 that would be great. I already get 21+mpg at 65mph on long distance trips. Around town, my fuel efficiency is only 16-17mpg at the moment. I'm hoping the JMS booster improves that as well as adding more in long distance drives.

The following is my ignition upgrade project pictures and notes.

If anyone knows where to find a same sized non-resistor spark plug that would replace what is currently used, please let me know. The feature size needs to be: Thread diameter - 14mm, Reach - 26.5mm, Seat type - Flat. Mission Ignition Systems used to carry an extended reach, zero OHM, iridium/rhodium plug that would have worked but their stock is depleted with no plans to restock. These are technically not street legal but their WeaponX coils supposedly do such a great job of EMI/RFI suppression that there would be no issue running these high performance racing plugs. I would settle for most any alternative that has a resistance of less than 5000 OHM just to squeeze every last drop of fuel efficiency out of my Pathfinder.

Well ... It was fun while it lasted, getting 24mpg on the highway and a decent boost accelerating from a stop and merging onto the highway, but the reliability of these Mission Ignition Systems' WeaponX coils just do not stand up to the test of time. I stripped out all the upgrades and put everything back to original condition with a new set of OE coils, which are one revision up from what was originally installed by Nissan. E-bay cost for the set was only $100.

I had to post this to satisfy my guilt for leading anyone astray in the future.

Good of you to report on long-term reliability. I'm curious - what was your total cost for that modification that yielded you a 10% increase in mpg?

The coils were installed in 2017 at a cost of $495. They were plug-and-play, nothing else needed but a couple of spacers for the wire harness on the passenger side, and the ROI more than covered that cost by the time I upgraded the system with the voltage booster less than 2yr ago. The booster was $420 plus another $150 for odds and ends. The ROI on that alone was not so good because I have not put many miles on the Pathfinder for the past couple of years. All in, the total cost of about $1100 was basically a wash in terms of ROI over 6yrs but it was lots of fun putting it all together. No regrets and nothing lost. Lots of time spent on this was worth it to me as a hobby project that went quite well for awhile. All good things like this come to an end, eventually. It still runs and performs very well, even for a 2002 Pathfinder.

Thanks! Some have asked for ideas for performance upgrades and yours is the first I've read about that didn't involve significant engine work.

If I was to start over, when I first needed coils 6yrs ago, I would have selected Z1 Off-Road High-Energy Ignition Coils instead but I never saw these at the time I was looking for high-output coils. Along with the Denso iridium tip-to-tip sparks plugs I am currently using , I may have gotten a comparable performance bang for the buck. If I find $350 to spare and nothing better to do, I may give those coils a try someday.