2004 WRX MPG drops

[Sam Soltan]

Has anyone else had a drastic MPG drop after a 15k service?
I was averaging 24/25 mpg and I am now getting less than 12 mpg. the service
said it was because of weather changes... seems like bs to me!

 

[Jim Stewart]

Has anyone else had a drastic MPG drop after a 15k service?
I was averaging 24/25 mpg and I am now getting less than 12 mpg. the service
said it was because of weather changes... seems like bs to me!

I've seen noticable changes with seasonal
change, but I think it's more because of
the gasoline formula changing and the computer
relearning it.

Try a tankful of Chevron premium and see
what happens. If it still stays at
12, you've got a problem.

 

[johninKY]

I know "summer" and "winter" gasolines are formulated differently, but a
50% reduction in fuel economy? It's either leaking somewhere or you are
pushing it through the engine. Check the spark plugs, looking for lots of
black fluffy deposits.