E3 Spark Plugs E3.48 Premium Automotive Spark Plug with DiamondFIRE Technology, 14mm, 0.750" Reach, Gasket Seat, Resistor, Pack of 1

I watch "Gears" (a show that admittedly looks like E3's bish...) and "Horsepower TV" and both shows tout the benefit of E3s design. I've read a lot of negative reviews, and a lot of positive reviews. At 300 miles so far, and all seems to working just great. (smooth idle, good power, increased mileage.....) but these plugs replaced plugs with 70k miles, the fuel filter was many months over due for replacement, and the tires were 10+ pounds low on pressure, so naturally my ride seems quite peppy and smooth. (94 Accord with a 2.2L standard trans). So I can say these plugs are an excellent replacement for the aged plugs, but I corrected too many problems with the rest of the ride to quantify that the plugs made my ride way better. My best MPG ever (city) was 28mpg, and the reason for all of the "fixes" was that my avg MPG was dipping towards 26. That said, if my MPG gets back to 28 or better, then these plugs are definitely a good investment.

I had been using the original E3.48 plug (gapping required) in our Generac XG8000E portable generator with great success for several years, so when it came time to do our yearly maintenance I purchased another E3.48 and a couple of extras for future maintenance replacements from Amazon.com. Generac recommends that the plug and oil/filter be changed every 100 hours of use or 1 year/season, which ever comes first. (The OEM plug for this unit is a Champion RC14YC and the E3.48 is the cross referenced replacement in the E3 lineup.) When I quickly ordered the new plugs I hadn't even noticed that the plug had been so radically changed to this new Diamond design until the plugs arrived! No Gap adjustment required huh? At first I was a bit dubious about putting one of these into the generator since the original version had worked so well after setting the proper gap (0.030) which the manual had stressed was vitally important for proper operation. But... I figured that I would never know if these actually worked in the Generac unless I tried one out, so I pulled the old E3.48 and installed one of these newer versions. I had been so pleased with the original E3 plug that I was wondering to myself if it would be difficult to locate and purchase the original version if this new design failed to work as well. I needn't have worried! :o) The generator fired right up without complaint and settled in to a nice smooth a noticeably quieter 30 minute test run. Since then the new plug has been working great with no issues at all, and just like the original E3 we had been using before, this plug makes a noticeable differerence in fuel consumption which is particularly important for a full house generator during our often days long winter storm caused power outages with daytime highs in the teens and low 20s! Weather conditions will often conspire to prevent you from heading down the mountain to the nearest gas station with power to refill our 4 five gallon reserve tanks we use for this unit. So obviously, the more runtime you can get out of every precious gallon of fuel the better! So... While our application is far from as demanding as those using these in a motor vehicle, reliability is no less important, so I thought I would post this review primarily for those who may be considering the use of this high tech spark plug in their portable generator. I can say that after running the E3 brand for the last three seasons, it is the only plug I will consider for our Generac! And based on the performance of the newer design so far, the new and improved E3.48 should do an even better job than the original design with the conventional GAP adjustment required design. And I do have to say that its nice to not have to worry about gapping the replacement plug anymore! One less thing to worry about when the time comes to do our yearly maintenance on the XG8000E!

I installed these in a 2000 Honda Civic Coupe EX. The first month I didn't see much of a change then boom! 4 mpg extra! My car is suppose to average 26 mpg highway and I'm now getting 30+mpg depending I keep my foot off the accelerator and put it on cruise. Its 04/06/2019 and plugs have performed great for the 2 years with 29 - 35 mpg. However within the past 2 weeks I kept getting a check engine light with misfire on cylinder 2 and 4. I found cylinder 4 the metal at the end had corroded and burnt away. Cylinder 2 appeared to have badly burnt sections. Gas mileage suffered 21 mpg. I replaced with Bosch Double Iridium after I did not receive any info for warranty replacement. I still regard these as an excellent replacement plug. Five Stars remains for the plug. As for the warranty phase - you be the judge.

Pros: Does give your engine a performance boost, hands down. Smoother acceleration curve. Gives a more responsive feel. Cons: Has some quality control manufacturing issues. One of the set had threads that were not 100% machine properly. Almost cross-thread my engine block. Causes a rise in engine temperature, maybe 1 - 3 degrees max. Gas-Saving: unknown, no tools to test that accurately. Other comments: If after you install these plugs you notice rough idle issues or similar, you have to reset your engine computer in order for it to run right. I called the E3 tech support and they said it should work fine out of the box. WRONG ! Installing it out of the box caused my 2000 civic to idle a bit rough. I had NGK plugs in it previously and it was noticeably smoother. So I reset the computer and that smoothed out the idle issue noticeably. Took it for a 35 mile trip and in the middle of the trip I noticed that when I am about to come to a complete stop, it felt as if the engine was about to die. I monitored it and on my return home that second issue smoothed out completely. Based on my observations I doubt that this plug can stand up to 100k miles or km, it just looks like a cheap plug. I hope it can last at least 40k, and i'll be fine with that. I read a lot before I purchased them, one thing I noticed was that no-one bothered to tune their engines immediately after the install. As soon as they noticed the poor idle, users took them out and threw them away. I guess thats why lawn mower users had such great reviews. Those engines don't need to be managed by a computer; it just needs a consistent spark to operate. So now you know what to do to fix that poor idle issue. Granted it might not fix the issue 100% but it should help a lot. That performance boost is what I was looking for many years and my next enhancement is to clean my fuel injectors. I will monitor these plugs and post an update in the future. I too am very curious what will happen down the road. If nothing negative further happens, I will use them as my goto plugs instead of NGKs. Nothing wrong with NGKs,They just max out when the engine is old, so you have to look else where to enhance an old engine, like mine. My car is a 2000 civic Ferio EK3. I cannot say if you will have the same positive experiences with your car, but it does indeed work with mine. Definitely better than iriduims (for me). Update: July 1, 2017. These plugs are still operating great. I bought two more sets. These are now my goto plugs. Another Update: March 30, 2018. These plugs are still going strong. I pulled them out and did some minor service on them. Used a brass brush to clean them up. I saw NO serious degradation in them. Just the usual discoloration in all plugs after thousand mile run. They still operate VERY well, therefore I back them 100%. I am still amazed by their operation (life, performance and stability). I still cannot vouch for the fuel saving aspect. Seems to use the same amount of fuel or slightly more. Update: Jun 1, 2019: The same set of plugs are still running good ! That's it folks. I call E3 a success story !

Replaced mu original NGK spark plugs after 135k kilometres. Car is running very smoothly (Golf MK5 2009 Pacific 2.0 FSI). Fuel efficiency seem to be bit better.

I've been using these on my MK5 jetta 2.5 for over 7 years with no issues. I am now using it on my MK6 Jetta 2.0. Highly recommend.

Excelente producto, tengo una mejoría en el rendimiento de mi vehículo, mayor potencia y un mejor comportamiento del motor.

Ces bougies sont parfaites j'ai un moteur qui tourne bien mieux j'ai l'impression qu'il est beaucoup plus réactif

Very hard to find spark plugs for ride on lawnmower