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
around.

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
present.

so the engine is running a bit more smoothly, but is not performing as
well in terms of fuel efficiency.

any ideas or suggestions?

 

<tockeyhockey@gmail.com> wrote in message
news:1163525749.582948.95460@e3g2000cwe.googlegrou ps.com...
>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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>
Air filters normally fit into recesses in their housings with a fair degree
of snugness in the fit so that the endseals can operate in their correct
manner to ensure that all intake air is drawn through (and not around) the
filter. Was the dimensional difference between the old and replacement
filter large enough to prevent proper sealing to take place. If you remove
the new filter again, if it has been in the housing for a few days you
should be able to see "witness" marks on it to show if it is seated properly
in the housing. If you are operating the engine in significantly dusty
conditions an improperly fitted filter will reduce the engine service life
as a consequence.

I assume that your engine is fuel injected and this will afford some measure
of self-regulation in the fuel air ratio, assuming the inlet manifold
pressure is higher due to the ill-fitting air filter. This tendency of
self-regulation of the fuel/ air ration will be less marked in the case of a
carburettor metered mix.

An over lean mixture can also result in reduced mileage, with less power
resulting in increased throttle openings to maintain anticipated speed.

The colour of your spark plug insulators may give you a coarse yardstick as
to the mixture correctness.

 

<tockeyhockey@gmail.com> wrote in message
news:1163525749.582948.95460@e3g2000cwe.googlegrou ps.com...
>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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>
Air filters normally fit into recesses in their housings with a fair degree
of snugness in the fit so that the endseals can operate in their correct
manner to ensure that all intake air is drawn through (and not around) the
filter. Was the dimensional difference between the old and replacement
filter large enough to prevent proper sealing to take place. If you remove
the new filter again, if it has been in the housing for a few days you
should be able to see "witness" marks on it to show if it is seated properly
in the housing. If you are operating the engine in significantly dusty
conditions an improperly fitted filter will reduce the engine service life
as a consequence.

I assume that your engine is fuel injected and this will afford some measure
of self-regulation in the fuel air ratio, assuming the inlet manifold
pressure is higher due to the ill-fitting air filter. This tendency of
self-regulation of the fuel/ air ration will be less marked in the case of a
carburettor metered mix.

An over lean mixture can also result in reduced mileage, with less power
resulting in increased throttle openings to maintain anticipated speed.

The colour of your spark plug insulators may give you a coarse yardstick as
to the mixture correctness.

 

<tockeyhockey@gmail.com> wrote in message
news:1163525749.582948.95460@e3g2000cwe.googlegrou ps.com...
>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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>
Air filters normally fit into recesses in their housings with a fair degree
of snugness in the fit so that the endseals can operate in their correct
manner to ensure that all intake air is drawn through (and not around) the
filter. Was the dimensional difference between the old and replacement
filter large enough to prevent proper sealing to take place. If you remove
the new filter again, if it has been in the housing for a few days you
should be able to see "witness" marks on it to show if it is seated properly
in the housing. If you are operating the engine in significantly dusty
conditions an improperly fitted filter will reduce the engine service life
as a consequence.

I assume that your engine is fuel injected and this will afford some measure
of self-regulation in the fuel air ratio, assuming the inlet manifold
pressure is higher due to the ill-fitting air filter. This tendency of
self-regulation of the fuel/ air ration will be less marked in the case of a
carburettor metered mix.

An over lean mixture can also result in reduced mileage, with less power
resulting in increased throttle openings to maintain anticipated speed.

The colour of your spark plug insulators may give you a coarse yardstick as
to the mixture correctness.

 

<tockeyhockey@gmail.com> wrote in message
news:1163525749.582948.95460@e3g2000cwe.googlegrou ps.com...
>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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>
Air filters normally fit into recesses in their housings with a fair degree
of snugness in the fit so that the endseals can operate in their correct
manner to ensure that all intake air is drawn through (and not around) the
filter. Was the dimensional difference between the old and replacement
filter large enough to prevent proper sealing to take place. If you remove
the new filter again, if it has been in the housing for a few days you
should be able to see "witness" marks on it to show if it is seated properly
in the housing. If you are operating the engine in significantly dusty
conditions an improperly fitted filter will reduce the engine service life
as a consequence.

I assume that your engine is fuel injected and this will afford some measure
of self-regulation in the fuel air ratio, assuming the inlet manifold
pressure is higher due to the ill-fitting air filter. This tendency of
self-regulation of the fuel/ air ration will be less marked in the case of a
carburettor metered mix.

An over lean mixture can also result in reduced mileage, with less power
resulting in increased throttle openings to maintain anticipated speed.

The colour of your spark plug insulators may give you a coarse yardstick as
to the mixture correctness.

 

You changed two variables at one time and, unfortunately, now have a
problem that might have been caused by either. So my suggestion is to
change one of the variables back and see what happens.

More than likely, it's not the air filter. Also, more than likely, your
old plugs are in a landfill someplace.

If it's any comfort: it's never happened to anyone else

Ken

tockeyhockey@gmail.com wrote:
> 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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>

 

You changed two variables at one time and, unfortunately, now have a
problem that might have been caused by either. So my suggestion is to
change one of the variables back and see what happens.

More than likely, it's not the air filter. Also, more than likely, your
old plugs are in a landfill someplace.

If it's any comfort: it's never happened to anyone else

Ken

tockeyhockey@gmail.com wrote:
> 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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>

 

You changed two variables at one time and, unfortunately, now have a
problem that might have been caused by either. So my suggestion is to
change one of the variables back and see what happens.

More than likely, it's not the air filter. Also, more than likely, your
old plugs are in a landfill someplace.

If it's any comfort: it's never happened to anyone else

Ken

tockeyhockey@gmail.com wrote:
> 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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>

 

You changed two variables at one time and, unfortunately, now have a
problem that might have been caused by either. So my suggestion is to
change one of the variables back and see what happens.

More than likely, it's not the air filter. Also, more than likely, your
old plugs are in a landfill someplace.

If it's any comfort: it's never happened to anyone else

Ken

tockeyhockey@gmail.com wrote:
> 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
> around.
>
> 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
> present.
>
> so the engine is running a bit more smoothly, but is not performing as
> well in terms of fuel efficiency.
>
> any ideas or suggestions?
>