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Over the years, countless companies have come up with devices claimed to reduce fuel consumption. The claims have ranged from plausible to the ridiculous. For example, wrapping magnets around your fuel line will not double your mileage and the only way you will ever get 200 mpg with a carburetor is to make it so small that air and fuel flow are so restricted that it can't possibly use more fuel than that. Of course your engine would produce so little power in the process as to be useless.
Spark plugs have long been a popular area for "innovation" of this sort. One of the latest comes in the form of the E3 spark plug featuring its DiamondFire electrode. This one falls into the plausible-but-unlikely category. Writer Larry Edsall recently undertook the latest iteration of a 5,000 mile annual road trip and decided to try out the E3 plugs. While E3 claims a 3-5 percent improvement in mileage, Edsall found his dipped from 20.11/19.98 the previous two years to 19.18 with the E3 plugs. He did all the usual maintenance like oil changes and tire pressures before leaving. Of course the vehicle was a year older and more worn which may have contributed to the dip. But even a fully scientific test with two or more vehicles running side by side in the same conditions (aside from the spark plugs) would probably yield a negligible difference at best. The E3 plugs aren't that pricey ($6-7 each) so if you do choose to try them it won't cost a lot. Just don't be too disappointed if you don't see much improvement in mileage.

[Source: Detroit News]


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  • 101 Comments
      • 5 Years Ago
      Watched the Horesepower Tv program where they tested the E3 plugs & reported HP gains. This may very well be true. HOWEVER, as this company was / is an advertiser for the show its unlikely the hosts would say "Geez... this product is Total Garbage" if it actually was.

      Consumer Reports have clearly denied advantages on some products that TV shows tested as great.

      For example I have seen programs advertize Zmax & even host the product on their program, yet Zmax is likely a scam; at least according to the governments lawsuits.
      • 5 Years Ago
      i have an 02 dodge neon i used bosch plugs and i got about 3 mpg more BUT... after only 6mo. mpg dropped,put in new bosch plugs and it went back up.did this twice and decided it wasnt worth the $6 ea.after only 6mo. i am an avid mpg junkie checking it every time,i say thumbs down to bosch for poor quality. ps if you do decide to get bosch plugs do not go to wal mart to get them.i saw that about every plug prong was different spacing, very inconsistent.(these were pre set 2 electrode plugs)
      • 7 Years Ago
      I've used these plugs in my yard machines(weed whacker, lawn mower) with good results. Both start much easier. Beyond that I can't say there was any other improvement I noticed. On the lawn mower I ran the weekend before with a new plug. So I can say that it wasn't a worn plug that was giving me the hard starting. It could be that these cheap motors have such weak spark at low rpm's that ny improvement is noticeable.

      ALl modern cars have pretty solid ignitions so there are probably no gains on a car.
      • 5 Years Ago
      I saw the horsepower episode that dyno'd the E3 spark plug and got the five horseposer gain. The test was controlled and to me conclusive. However, you must remember that those "maximum" HP & torque results are in the upper RMP ranges that few of us dirve in or around. Unless of course you are takeing your daily commuter out to the quartermile race track on week ends. Since I had put 40,000 mile on my 85 vette's bosh platnums, I thought I'll give E3's a try. Since the Vette gets 20 in town 26 mpg Hwy@75mph using cruise control consistantly. As of late(due to old Plugs Iam sure)is getting 15 and 22 respectively. Now with new tires, alignment and E3's we shall see!! I will report back in 72 hours after a 200 hwy mile cruise. Also I am in sales as well and do around 50 to 100 mile a day combined driving. See ya soon
      • 5 Years Ago
      Come on guys, a spark plug is a spark plug !!! I've been in the automotive business for over 45 years now and have seen it all. You don't get any constant or multiple sparks with an E3, you only get 1 spark per combustion cycle just like any other spark plug. Those of you who "think" that you see or feel gains, well I hate to tell you, but it's either in your mind or caused by other factors. An E3 works about as good as those fuel line magnets for helping your gas mileage. If you want one of those fancy long duration sparks, you need to buy an MSD. That's what they use to produce the spark on the E3 commercials !!
      • 4 Years Ago
      I bought a set of e3 plugs for my 1953 Jeep Pickup! After less than 100 miles it burnt a hole through #4 piston. I hate to think that a sparkplug would do this, but I have been driving this truck 3 to 4 times a week for 6 years with no problams. I just wanted to change the plugs and wires. As of right now I have no answer. And for you nay sayers I have been an Auto tech. for soon to be 40 years, and cut my teeth on the F and L head motors. This 131 cid F head i 4 had on bad habbits at all.
      • 4 Years Ago
      I have a lawn mower with a 4.5HP engine, it has the E3.10 spark plug and the engine starts on the first pull but that is nothing special because it always does, but now the engine runs a few minutes and cuts out. When you restart the engine it runs a few minutes and cuts out again, it keeps doing that through out the entire time of cutting the grass. Has anyone had the same problem?
      • 5 Years Ago
      About a month after installing the E3 plugs in my 2006 Jeep Wrangler 6 Cylinder with only 30K miles the problem started. When I would come to a stop the and start to take off the Jeep would stumble and almost die and then take off. This would happen about twice a week and never caused the computer to store a code. After having the plugs in for four months, I replaced everything, MAP sensor, Crankshaft sensor, checked fuel filter, fuel pump, and then decided to replace the expensive E3 plugs with a cheap set of plugs and that solved the problem. I warn everyone that comes into my shop never to buy these plugs.
      • 7 Years Ago
      I replaced spark plugs in my 99 Plymouth Grand Voyager 10000 miles ago with E3's. Car started missing and hesitating in November. I suspected and replaced many parts and the hesitation continued. I checked and went through everything else on the van before deciding to go back and check the spark plugs. The E3's were the problem all along. they were completely fouled out. I replaced them with oem parts and the van has been running perfect ever since. What scares me is that I Put the E3's in my other cars also. time will tell! I will not use E3's again
        • 4 Months Ago

        I tried E3 plugs in my 04 Mercury Mountaineer. One of the plugs didn't
        work, causing my catalytic converter to become clogged. I will never use them again. The mechanic at the Ford dealership, told me that my
        car was the fourth one he has seen with the similar problem.
      • 4 Years Ago
      Hey there khaki71 the same thing happened to my 2002 Chevy Malibu but only after 2 days. And I lost the receipt for the plugs. I had new plugs installed and NO problem at all.
      • 4 Months Ago
      Just saw the Horsepower TV episode. After watching that then reading here, it seems the E3's are good in everything except Fords. And maybe Audi turbos. Which sucks for me as I have a 04 Ranger 3.0. I just changed the plugs in my daughters 03 PAssat 1.8T. Anybody tried it in those?
      • 4 Months Ago
      Made a big difference on my 95 GMC Sierra. Better performance too...
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