btw i have done plugs, rotor arm + cap + leads. this made a massive difference on performance!!
and to the mpg ?
just chucked in refilled mine - done roughly 140 miles on £30 mainly all short journey and traffic etc and cold weather and extended warmup etc.
had a run tonight once it was warm down a 3 mile straight i know
short trips work/town and cold weather usually i'm lucky if i average 15mpg