infiniti i30 engine a it lacking in power

My trusted Maxima decided to crap out a few days before our planned
road trip (MAF gone bad?). I probably don't have time to diagnose/fix
the issue before the trip.

I may need to use my wife's car for the trip. It is a 99 Infiniti i30.
The ONLY issue that bother's me a bit and makes me a little hesitant
is the engine. Comparing to my Maxima (while it was operating normally
, the engine has a sutble vibration under load. I can feel it in the
gas paddle when I accelerate.

I put in new spark plugs, changed engine oil, replaced air filter, no
change. I don't know the status of the coil packs. It idles fine.
Could a dirty MAF sensor cause the sympton? HP should be very similar
to my maxima, but it just doesn't seem as responsive with the suble
vibration. (the engine makes a deep humming sound under load and this
is when the vibration occurs). The engine oil seems slightly
overfilled, could that have caused it?

A mechanic test drove the car while diagnose a different problem, and
said the engine is fine. So it's probably not too out of spec, but it
doesn't feel quite right. It does make long trip slightly less
enjoyable as I find myself let go of the gas, and press it again to
see if I can reduce the hum..

I was going to delay diagnose this until a bit later, but the maxima
craping out moved up the priority a bit.

Thanks!

Raymond

On Dec 17, 1:36*am, wrote:
> My trusted Maxima decided to crap out a few days before our planned
> road trip (MAF gone bad?). I probably don't have time to diagnose/fix
> the issue before the trip.
>
> I may need to use my wife's car for the trip. It is a 99 Infiniti i30.
> The ONLY issue that bother's me a bit and makes me a little hesitant
> is the engine. Comparing to my Maxima (while it was operating normally
> , the engine has a sutble vibration under load. I can feel it in the
> gas paddle when I accelerate.
>
> I put in new spark plugs, changed engine oil, replaced air filter, no
> change. I don't know the status of the coil packs. It idles fine.
> Could a dirty MAF sensor cause the sympton? HP should be very similar
> to my maxima, but it just doesn't seem as responsive with the suble
> vibration. (the engine makes a deep humming sound under load and this
> is when the vibration occurs). The engine oil seems slightly
> overfilled, could that have caused it?
>
> A mechanic test drove the car while diagnose a different problem, and
> said the engine is fine. So it's probably not too out of spec, but it
> doesn't feel quite right. It does make long trip slightly less
> enjoyable as I find myself let go of the gas, and press it again to
> see if I can reduce the hum..
>
> I was going to delay diagnose this until a bit later, but the maxima
> craping out moved up the priority a bit.
>
> Thanks!
>
> Raymond

If all thats wrong with the Maxima is the MAF, why not swap the one
from the i30 onto it & see if it fixes the problem? You can always
put it back on the the I30 when you get back from the trip.

e.meyer > wrote:

> If all thats wrong with the Maxima is the MAF, why not swap the one
> from the i30 onto it & see if it fixes the problem? You can always
> put it back on the the I30 when you get back from the trip.

yes I could. But if In the process I mess up the Infiniti as well,
then I am really screwed. At least now it's an OK backup.

I am going to clean the MAF and see how it goes...

Raymond

wrote:

> I may need to use my wife's car for the trip. It is a 99 Infiniti i30.
> The ONLY issue that bother's me a bit and makes me a little hesitant
> is the engine. Comparing to my Maxima (while it was operating normally
> , the engine has a sutble vibration under load. I can feel it in the
> gas paddle when I accelerate.

Ok I found out the oil level in the engine is too high. I forgot to
check it after I did my last oil change. I gave the shop 5 QTs of
5w30, and the stupid guy probably dumped the whole thing in it as he
didn't return me the half bottle. (my car takes 4.25 QT)

With the correct oil level, and driving this car more, I think I have
a better description of this problem.

At RPM 1000-2000 (about 40-50 miles, when the engines shifts gears and
the engine drops to 1.5k RPM from 2k+ RPM), There's a subtle hum from
the engine. This can be felt both in the gas peddle, and the sound of
the engine. The hum can also be felt during initial acceleration from
a stop, but it goes away pretty fast as the car picks up speed.

At normal highway crusing speed at 2.5k RPM, even under load with 5
people in the car and some cargo, it runs fine and I don't feel a lack
of power, the engine is also quiet, just like my Maxima. Perhaps the
slight lack of power I felt was due to the incorrect oil level.

What would be the cause of this hum at 1.5k RPM? Do I need an engine
tune up?

The car has 70K on it, has 5w30 synthetic oil. I changed the spark
plugs a month ago with OEM plugs and new air filter. (and that's about
all I know how to do. The hum was there when I first bought the car
2 month ago, the maintenance I did improved performance but the hum
never went away.

This car is known for its ignition coil failures (I replaced all 6 on
my Maxima and this car is the same year, but half the miles, and I
believe is still running on the original coils). Could a coil that's
not working in top condition cause this?

Raymond

On Jan 6, 3:47*pm, wrote:
> wrote:
> > I may need to use my wife's car for the trip. It is a 99 Infiniti i30. *
> > The ONLY issue that bother's me a bit and makes me a little hesitant
> > is the engine. Comparing to my Maxima (while it was operating normally
> > , the engine has a sutble vibration under load. I can feel it in the
> > gas paddle when I accelerate.
>
> Ok I found out the oil level in the engine is too high. I forgot to
> check it after I did my last oil change. I gave the shop 5 QTs of
> 5w30, and the stupid guy probably dumped the whole thing in it as he
> didn't return me the half bottle. (my car takes 4.25 QT)
>
> With the correct oil level, and driving this car more, I think I have
> a better description of this problem.
>
> At RPM 1000-2000 (about 40-50 miles, when the engines shifts gears and
> the engine drops to 1.5k RPM from 2k+ RPM), There's a subtle hum from
> the engine. This can be felt both in the gas peddle, and the sound of
> the engine. The hum can also be felt during initial acceleration from
> a stop, but it goes away pretty fast as the car picks up speed.
>
> At normal highway crusing speed at 2.5k RPM, even under load with 5
> people in the car and some cargo, it runs fine and I don't feel a lack
> of power, the engine is also quiet, just like my Maxima. Perhaps the
> slight lack of power I felt was due to the incorrect oil level.
>
> What would be the cause of this hum at 1.5k RPM? Do I need an engine
> tune up?
>
> The car has 70K on it, has 5w30 synthetic oil. I changed the spark
> plugs a month ago with OEM plugs and new air filter. (and that's about
> all I know how to do. The hum was there when I first bought the car
> 2 month ago, the maintenance I did improved performance but the hum
> never went away.
>
> This car is known for its ignition coil failures (I replaced all 6 on
> my Maxima and this car is the same year, but half the miles, and I
> believe is still running on the original coils). Could a coil that's
> not working in top condition cause this?
>
> Raymond

How many miles are on the car and is it a manual tranny that has been
driven in an, um, enthusiastic manner? My first thought is a weak
engine mount allowing a little more of the engine's natural vibration
to be transmitted to the chassis where it is resonating. This is only
a guess however and really with a description like you give one would
have to drive/hear the car to make a diagnosis with any degree of
certainty. Not that your description was poor but that kind of noise
could be any number of things.

nate

N8N > wrote:

> > The car has 70K on it, has 5w30 synthetic oil. I changed the spark
> > plugs a month ago with OEM plugs and new air filter. (and that's about
> > all I know how to do. The hum was there when I first bought the car
> > 2 month ago, the maintenance I did improved performance but the hum
> > never went away.

> How many miles are on the car and is it a manual tranny that has been
> driven in an, um, enthusiastic manner? My first thought is a weak
> engine mount allowing a little more of the engine's natural vibration
> to be transmitted to the chassis where it is resonating. This is only
> a guess however and really with a description like you give one would
> have to drive/hear the car to make a diagnosis with any degree of
> certainty. Not that your description was poor but that kind of noise
> could be any number of things.

The car has about 75k on it. It is a 99 infiniti i30. It's an
automatic transmission. I don't know how it's driven by the previous
owner. My guess is average driving. It's mostly local street level
driving by the parents, hence the low miles.

Raymond