Spark Plugs

[BikeRider]

I was thinking about changing the stock plugs with some new ones at 40k or so, but was unsure of which type to use. Anybody have any luck upgrading to the gimmick type spark plugs like the Split Fire? What mileage is every one changing them (I know what the manual says)? Are there any changes in idle, gas mileage, or HP's?

 

[Guest]

plugs

I've got 116K miles on my 1998 4x4 with 5.4 and 3.73 rear with the original plugs. It still runs like a top and I get 14 mpg around town and 16 - 17 on the highway. I can't complain one bit. I do plan to change the plugs soon just on principle not because of any problems. You can believe that I will be putting the stock motorcraft plugs back in there.

Rob in PA