Gas milage went to the sh1t all of a sudden... What gives

[xpl0sive]

so i noticed today that my gas milage has dropped dramatically... Before it used to consume 15l/100km, now its at 21L/100km... the car is a 2001 4.2.
I did an oil change about 1000km ago, always put at elast 91 octane gas in... the only thing i can think of is a dirty MAF or sparkplugs need changing... you guys have any other ideas...
btw 15L/100km = 16MPG <<<wasnt the greatest to begine with, i do pretty much all city driving sometimes iwth a heavy foot
and 21L/100KM = 11MPG...

i haven't changed my driving style or anything, so why do I get the milage of a hummer?

[GFRRS3]

Id change, plugs, air filter and clean the MAF, then see if there is a difference. Im getting 30+MPG HWY with my 1.8T.

[xpl0sive]

i'll do that this weekend, any other ideas?