Review on E3 Spark Plugs E3.72 Automotive Spark Plug: Enhancing Engine Performance, Pack of 1! by James Stevenson

My 1992 Ford F-150 4.9 liter engine had to do a lot of miles to set up but otherwise worked great . Decided to try them out to see if I could get a little more power or better gas mileage than they claimed. They've been in the field for over a month and since the start of the installation the trucks' acceleration has been slowing down and idling horribly overspeed. I am very disappointed as they cost twice as much as standard plugs and now need to be replaced. The cover, rotor and connector cable are OEM specs, so that's not it. I do not offer them and I am very dissatisfied.