Hello,

First post for me - I just joined. Hope my photos upload.

I have a '95 F-250 - six cyl 300. Runs fine but the Motorcraft SP-435 plugs always look like this when replaced - all six look pretty much alike.

I really like the Ford 300, and run them in several '66 Ford trucks with carbs and Duraspark II conversions. Used plugs look fine from those engines.

Is this a timing problem or fuel? I'm not real comfortable working with FI yet and all the electronics.

thanks,
Doug

 

How much oil does the engine use? How many miles on those plugs?

 

That's oil ash.

 

Agree. Usually caused by additives or changing to different oils. Can go deeper to worn valve guides or seals or both.