Do Sparkplugs make a difference?

[Sambo92]

Hey Guys and Gals! 

I recently passed my driving test and brought an 05 plate Ford Focus, after buying my car and getting it home, My Brother suggested doing a service on it.

I brought new Sparkplugs, oil, Air Filter all the normal stuff and because he has done all his own services, to save money mainly I think! 

Any how, since the 'service' I have been using alot of fuel, like I mean alot of fuel! I live 5miles away from work and only work 4 days a week, but still I use nearly half a tank of fuel during them days.. without making any additional trips!

So I wondered if the type of Sparkplug I brought has any affect on that? Ive attached a picture of the Sparkplugs I brought, when putting them in I noticed the ends were different to conventional Sparkplugs? 

Any advice would be greatly appreicated

Many Thanks

Sam

[Micro]

Brim the tank, drive for 4 days, then brim the tank again, work out your MPG from that and see if the engine really is using that much fuel, or if your fuel sender is faulty.

I think you'd notice using 25L of fuel instead of closer to 5L! Your car must smell beautifully rich!