Review on Bosch 9613 Double Iridium Longer by Mike Lawler

I installed them on my 2007 Toyota FJ Cruiser. immediately noticed the truck running much smoother and also noticed a slight improvement in fuel economy over the course of a few weeks. Overall the truck runs better than before (this has been compared to normal Toyota dealer spark plugs). Not relevant but noteworthy. (I don't run my tank dry, not a good idea living in the country) so the entire run is 1/8 tank of gas. My FJ is a premium fuel car, which means it must run on at least 91 octane. After the mandatory ethanol law was passed, all gas stations in my area switched to 87 octane. Driving on 91+ octane I barely got 250 miles to a tank of gas, under the mandatory ethanol law I was forced to drive on 87 octane 10% ethanol and I could only drive 175 miles to a tank of gas. (big drop didn't like this one) I installed a Bosch Iridium fine wire spark plug which increased the gas mileage to about 200 miles on one tank of gas. Then the oil was changed from regular Toyota oil to Mobil One synthetic motor oil and a K&N air filter. I now drive 300 miles on one tank of gas, which is better than my truck ever did. 20 mpg HWY with 1/8 tank of gas to go. :)