rocknrun
Full Access Member
A couple of weeks ago I changed the spark plugs in my recently acquired 04 KJ, which has 89,000 miles on it. The plugs I pulled out were NGK spark plugs and in bad shape; the center electrodes were really worn down, barely sticking out from the ceramic. Put in Autolite Double Platinums and was looking forward to a MPG improvement, instead my MPG has dropped by about 2 MPG. Any ideas?