Taurus Stumbles on Acceleration

My 2004 Taurus has developed a stumble on acceleration. It only does it
after it's been idling for a while, like at a long light. It seems to idle
fine but when I give it gas when the light turns green it will stumble a
few times and then runs fine. If it was carb'ed I'd suspect the
acceleration pump. At shorter stops it does not do it and otherwise seems
to run fine. Gas mileage has not changed. It has about 35K miles and is the
2 valve 3.0l engine. Plugs were replaced a few months ago and the air
filter was replaced at the last oil change. The check engine light is not
on. Any sugestions what to check? Thanks...

ZZ wrote:
> My 2004 Taurus has developed a stumble on acceleration. It only does it
> after it's been idling for a while, like at a long light. It seems to idle
> fine but when I give it gas when the light turns green it will stumble a
> few times and then runs fine. If it was carb'ed I'd suspect the
> acceleration pump. At shorter stops it does not do it and otherwise seems
> to run fine. Gas mileage has not changed. It has about 35K miles and is the
> 2 valve 3.0l engine. Plugs were replaced a few months ago and the air
> filter was replaced at the last oil change. The check engine light is not
> on. Any sugestions what to check? Thanks...

This sounds like an interesting problem. I will be curious to know the
outcome.
Does this happen all the time or only once the engine is fully warmed
up, or only while warming up?
Will it do this if you put it in neutral during the extended idle? Does
the idle speed seem correct. Does it idle faster if you put it in
neutral.?
Check the duct from the air filter box to the throttle body and make
sure the clamps are tight and there are no air leaks.

BTW, I have checked ALLDATA and do not see any TSB listed for these
symptoms.

Kevin

Kevin Mouton wrote:
> This sounds like an interesting problem. I will be curious to know the
> outcome.
> Does this happen all the time or only once the engine is fully warmed
> up, or only while warming up?
> Will it do this if you put it in neutral during the extended idle? Does
> the idle speed seem correct. Does it idle faster if you put it in
> neutral.?
> Check the duct from the air filter box to the throttle body and make
> sure the clamps are tight and there are no air leaks.
>
> BTW, I have checked ALLDATA and do not see any TSB listed for these
> symptoms.
>

Actually, it's most noticeable when I pull on to the freeway in the
morning on the way to work. I drive about two miles from my house to the
freeway and then usually have to idle along the on-ramp for a hundred
yards or so (we have metered ramps so the traffic backs up there). When
it's my turn and I accelerate onto the fway is when I notice it most.
When I first get on it, it will stumble a couple times and then takes
off and is fine after that. It doesn't seem like it's about to stall, it
just hesitates when I give it gas. I get off the fway about four miles
from work and I don't usually notice it at the lights there, altho
they're usually pretty short. Going home is the reverse path but it
seems to run OK then. Getting on the fway in the morning is usually my
longest traffic wait.

Then, the other day I had stopped at a store for about 10 mins and when
I came out it started fine but when I put it in R to back out of the
parking space it ran very rough and almost stalled so I slipped it into
N and revved it a little and then it was OK. That was about the worst
it's been. My Astro van behaved much the same way before I cleaned its
IAC...perhaps it's a similar problem, altho the IAC is different on the
Taurus (I don't think they even call it that).

Idle speed seems OK...about 750 rpm on the tach and steady. It doesn't
change when putting into neutral.

When I changed the oil last I also changed the air filter. While I was
at it I took the air intake hose loose at the throttle body and found a
lot of carbon on the butterfly and inside. I dosed it with TB cleaner
and swabbed it out. It seemed to idle & accelerate a bit better after
that (might just be wishful thinking :-). That was more than a month ago
and it was fine until a couple weeks age. I did check for loose vacuum
lines, etc, but will take a closer look at clamps, etc.

It's not real bad at the moment but I'd like to prevent something more
serious. Certainly not as serious as many of the tales of woe on here.
It is annoying, tho. The car has run fine until this started a couple
weeks ago.

Anyway, some more data. Thanks for the reply. If you have any other
ideas, they'll be much appreciated...

"M.M." > wrote in message
news:eKpfg.102250$iU2.90141@fed1read01...
> Kevin Mouton wrote:
> > This sounds like an interesting problem. I will be curious to know the
> > outcome.
> > Does this happen all the time or only once the engine is fully warmed
> > up, or only while warming up?
> > Will it do this if you put it in neutral during the extended idle? Does
> > the idle speed seem correct. Does it idle faster if you put it in
> > neutral.?
> > Check the duct from the air filter box to the throttle body and make
> > sure the clamps are tight and there are no air leaks.
> >
> > BTW, I have checked ALLDATA and do not see any TSB listed for these
> > symptoms.
> >
>
> Actually, it's most noticeable when I pull on to the freeway in the
> morning on the way to work. I drive about two miles from my house to the
> freeway and then usually have to idle along the on-ramp for a hundred
> yards or so (we have metered ramps so the traffic backs up there). When
> it's my turn and I accelerate onto the fway is when I notice it most.
> When I first get on it, it will stumble a couple times and then takes
> off and is fine after that. It doesn't seem like it's about to stall, it
> just hesitates when I give it gas. I get off the fway about four miles
> from work and I don't usually notice it at the lights there, altho
> they're usually pretty short. Going home is the reverse path but it
> seems to run OK then. Getting on the fway in the morning is usually my
> longest traffic wait.
>
> Then, the other day I had stopped at a store for about 10 mins and when
> I came out it started fine but when I put it in R to back out of the
> parking space it ran very rough and almost stalled so I slipped it into
> N and revved it a little and then it was OK. That was about the worst
> it's been. My Astro van behaved much the same way before I cleaned its
> IAC...perhaps it's a similar problem, altho the IAC is different on the
> Taurus (I don't think they even call it that).
>
> Idle speed seems OK...about 750 rpm on the tach and steady. It doesn't
> change when putting into neutral.
>
> When I changed the oil last I also changed the air filter. While I was
> at it I took the air intake hose loose at the throttle body and found a
> lot of carbon on the butterfly and inside. I dosed it with TB cleaner
> and swabbed it out. It seemed to idle & accelerate a bit better after
> that (might just be wishful thinking :-). That was more than a month ago
> and it was fine until a couple weeks age. I did check for loose vacuum
> lines, etc, but will take a closer look at clamps, etc.
>
> It's not real bad at the moment but I'd like to prevent something more
> serious. Certainly not as serious as many of the tales of woe on here.
> It is annoying, tho. The car has run fine until this started a couple
> weeks ago.
>
> Anyway, some more data. Thanks for the reply. If you have any other
> ideas, they'll be much appreciated...

Well. Ford says not to clean the IAC on that one. The solvent can get into
the electrical windings and deteriorate the insulation. Perhaps you damaged
it when you cleaned the throttle body to which the IAC is mounted. It just
took a while for the insulation to fail. Just a possibility, and from the
symptoms probably something else anyway.

--
Kevin Mouton
Automotive Technology Instructor
"If women don't find you handsome, they should at least find you handy"
Red Green

"Kevin" > wrote in
news:t8rfg.52286$9c6.27929@dukeread11:


>
> Well. Ford says not to clean the IAC on that one. The solvent can get
> into the electrical windings and deteriorate the insulation.



Are there any other models/manufacturers that recommend not to clean their
IACs?

I ran a bit of throttle body cleaner through my Integra's two years in a
row. So far no problems, but now you've got me wondering...


--
TeGGeR®

TeGGeR® wrote:

> Are there any other models/manufacturers that recommend not to clean their
> IACs?
>
> I ran a bit of throttle body cleaner through my Integra's two years in a
> row. So far no problems, but now you've got me wondering...
>

On my Chevy Astro they say to not get solvent into the electrical part.
The way it's made, it was pretty easy to clean just the business end. It
sure needed it and it made quite a difference.

Kevin wrote:
> Well. Ford says not to clean the IAC on that one. The solvent can get into
> the electrical windings and deteriorate the insulation. Perhaps you damaged
> it when you cleaned the throttle body to which the IAC is mounted. It just
> took a while for the insulation to fail. Just a possibility, and from the
> symptoms probably something else anyway.
>

I suppose that's a possibility. Altho, the IAC is on the side of the TB
so the solvent probably wouldn't flood into it as if it were lower. I
did take the IAC off and look at it the other day. It looked kinda gunky
but not all that bad. I think Alldata (I have a sub for the car) has
some specs for the IAC so I'll dig out the ohmmeter some time soon and
check that out.

I just now took a look at the intake hose clamps, vacuum lines (there's
sure a bunch of them), checked the hose for cracks, etc. It all looks
good. I'll keep an eye on it and see if it gets worse. If it does, I'll
get more serious about it. Maybe it'll eventually throw a code so we'll
have a better idea what's going on. At any rate, thanks for the
pointers...much appreciated...

On Wed, 31 May 2006 20:10:48 -0500, "Kevin" > wrote:

>
>"M.M." > wrote in message
>news:eKpfg.102250$iU2.90141@fed1read01...
>> Kevin Mouton wrote:
>> > This sounds like an interesting problem. I will be curious to know the
>> > outcome.
>> > Does this happen all the time or only once the engine is fully warmed
>> > up, or only while warming up?
>> > Will it do this if you put it in neutral during the extended idle? Does
>> > the idle speed seem correct. Does it idle faster if you put it in
>> > neutral.?
>> > Check the duct from the air filter box to the throttle body and make
>> > sure the clamps are tight and there are no air leaks.
>> >
>> > BTW, I have checked ALLDATA and do not see any TSB listed for these
>> > symptoms.
>> >
>>
>> Actually, it's most noticeable when I pull on to the freeway in the
>> morning on the way to work. I drive about two miles from my house to the
>> freeway and then usually have to idle along the on-ramp for a hundred
>> yards or so (we have metered ramps so the traffic backs up there). When
>> it's my turn and I accelerate onto the fway is when I notice it most.
>> When I first get on it, it will stumble a couple times and then takes
>> off and is fine after that. It doesn't seem like it's about to stall, it
>> just hesitates when I give it gas. I get off the fway about four miles
>> from work and I don't usually notice it at the lights there, altho
>> they're usually pretty short. Going home is the reverse path but it
>> seems to run OK then. Getting on the fway in the morning is usually my
>> longest traffic wait.
>>
>> Then, the other day I had stopped at a store for about 10 mins and when
>> I came out it started fine but when I put it in R to back out of the
>> parking space it ran very rough and almost stalled so I slipped it into
>> N and revved it a little and then it was OK. That was about the worst
>> it's been. My Astro van behaved much the same way before I cleaned its
>> IAC...perhaps it's a similar problem, altho the IAC is different on the
>> Taurus (I don't think they even call it that).
>>
>> Idle speed seems OK...about 750 rpm on the tach and steady. It doesn't
>> change when putting into neutral.
>>
>> When I changed the oil last I also changed the air filter. While I was
>> at it I took the air intake hose loose at the throttle body and found a
>> lot of carbon on the butterfly and inside. I dosed it with TB cleaner
>> and swabbed it out. It seemed to idle & accelerate a bit better after
>> that (might just be wishful thinking :-). That was more than a month ago
>> and it was fine until a couple weeks age. I did check for loose vacuum
>> lines, etc, but will take a closer look at clamps, etc.
>>
>> It's not real bad at the moment but I'd like to prevent something more
>> serious. Certainly not as serious as many of the tales of woe on here.
>> It is annoying, tho. The car has run fine until this started a couple
>> weeks ago.
>>
>> Anyway, some more data. Thanks for the reply. If you have any other
>> ideas, they'll be much appreciated...
>
>Well. Ford says not to clean the IAC on that one. The solvent can get into
>the electrical windings and deteriorate the insulation. Perhaps you damaged
>it when you cleaned the throttle body to which the IAC is mounted. It just
>took a while for the insulation to fail. Just a possibility, and from the
>symptoms probably something else anyway.

Kevin you are right -- its probably something else. IAC problems will
not cause stumble when hyou open the throttle. With an open throttle
it is irrelevant what the IAC is doing. IACs cause stalling or racing
with the foot of the gas.

I would clean the mass air flow sensor -- very common problem.

Don
www.domsautomotive.com