Thank You for all that you do!
I have a 2009 Mercedes R350. I bought it with 54k miles on it and it now has 147k. I changed the plugs and used iridium plugs, the ones pulled out were NGK Platinum. My MPG was 16/21. I gaped them at .032 and I am now getting 19/23, wow!
I'm on my 2nd tank of gas and still getting the better MPG. I've read different stories on bigger gaps produces better MPG. When I pulled out the old plugs , they were worn down to .050..Anny ideas to this great phenomenon?