i put in a "supposedly" OE air filter made by mahle a couple of months
ago. i noticed at the time that the filter was slightly larger than
the one i was removing (which was original stock equipment). i put it
in anyway, since the difference in size was less than a centimeter all
first of all, do air filters shrink a bit as the age? if so, that
might explain why the difference exists.
secondly, and this is more worrisome -- since i changed the air filter
(i also put in four bosch iridium spark plugs), my gas mileage has
dipped by about 5 mpg on the highway.
could that "too big" air filter be causing air flow problems?
also, my slightly choppy engine idle, which was present before the
changes, is still there, but a little less noticiable -- you might call
it "intermitent light chop" in airline terms. minor, and not always
so the engine is running a bit more smoothly, but is not performing as
well in terms of fuel efficiency.
any ideas or suggestions?