Our 2004 Pontiac Bonneville GXP has developed a low speed miss. It is particularly noticeable when
the engine is cold. It seems to miss only at idling speed and is worse before the engine warms up.
The miss goes away when you load the engine under acceleration. At only 36000 miles it shouldn't
need a major tune-up. I am guessing a dirty fuel injector. Any ideas appreciated.

Bob Swinney

On Wed, 25 Feb 2009 20:06:07 -0600, "Robert Swinney"
wrote:

Our 2004 Pontiac Bonneville GXP has developed a low speed miss. It is particularly noticeable when
the engine is cold. It seems to miss only at idling speed and is worse before the engine warms up.
The miss goes away when you load the engine under acceleration. At only 36000 miles it shouldn't
need a major tune-up. I am guessing a dirty fuel injector. Any ideas appreciated.

Bob Swinney
==========
Try the cheap fix first.

Add two cans of Berryman's B-12 FI cleaner to about 20 gallons of
gas and run that through the system.
http://www.berrymanproducts.com/Default.aspx?tabid=140

If this solves the problem you may want to start buying your gas
at another station.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

On Wed, 25 Feb 2009 20:06:07 -0600, "Robert Swinney"
wrote:

Our 2004 Pontiac Bonneville GXP has developed a low speed miss. It is particularly noticeable when
the engine is cold. It seems to miss only at idling speed and is worse before the engine warms up.
The miss goes away when you load the engine under acceleration. At only 36000 miles it shouldn't
need a major tune-up. I am guessing a dirty fuel injector. Any ideas appreciated.

Bob Swinney

Silly question number one: Is it throwing a computer code and
lighting the Check Engine Light? And if so, what are the codes?

If it's enough to worry about, the OBD-II computer will notice it.

Only at idle, worse when cold... You might be right about a dirty
injector. Try some Chevron Techron additive in the tank first.

If that doesn't work, buy or borrow a fuel-rail connected injector
cleaning kit and a can of the cleaning solvent. The kit costs about
what you'd pay to have it done once, and if you are careful to buy a
decent one it will be good for many years.

-- Bruce --

"Robert Swinney" wrote:

Our 2004 Pontiac Bonneville GXP has developed a low speed miss. It is particularly noticeable when
the engine is cold. It seems to miss only at idling speed and is worse before the engine warms up.
The miss goes away when you load the engine under acceleration. At only 36000 miles it shouldn't
need a major tune-up. I am guessing a dirty fuel injector. Any ideas appreciated.

Bob Swinney


If it was my car, I'd say my number 1 intake runner gasket failed again. Try spraying
some brakekleen near intake / head junction and see if engine tone changes.

Wes

Thanx to all repliers. The car is now in the hands of local, (capable ?) Pontiac, Buick, GMC
dealer's service department. Business must be way off there. Right off the bat the service advisor
tried to sell me some after-warranty "chemical" insurance when I explained the suspected injector
problem. I opted out of course.

Bob Swinney
"Wes" wrote in message ...
"Robert Swinney" wrote:

Our 2004 Pontiac Bonneville GXP has developed a low speed miss. It is particularly noticeable when
the engine is cold. It seems to miss only at idling speed and is worse before the engine warms up.
The miss goes away when you load the engine under acceleration. At only 36000 miles it shouldn't
need a major tune-up. I am guessing a dirty fuel injector. Any ideas appreciated.

Bob Swinney


If it was my car, I'd say my number 1 intake runner gasket failed again. Try spraying
some brakekleen near intake / head junction and see if engine tone changes.

Wes

On Thu, 26 Feb 2009 08:58:21 -0600, "Robert Swinney"
wrote:

Thanx to all repliers. The car is now in the hands of local, (capable ?) Pontiac, Buick, GMC
dealer's service department. Business must be way off there. Right off the bat the service advisor
tried to sell me some after-warranty "chemical" insurance when I explained the suspected injector
problem. I opted out of course.

Business IS way off, the New Car Sales side of the house at some
dealers has dropped 90% or more.

So the Service side of the house has been co-opted by the Gods Of
Profit to push many (usually of dubious utility) flushing services as
a form of prerventative maintenance. Radiator flushes, intake
cleaning, transmission flushes, final drive gears, oil system flushes,
power steering, brakes, air ducts in the Heater and Air
Conditioning...

You name a system, and they have a way to apply a vacuum cleaner to
your wallet to flush all the excess cash out of it.

Brake Bleeding $40 - Brake Flushing Service $129 for the same thing,
just done by an impressive looking machine that they wheel up to the
car and wave their hands while chanting "Ohwatta Foolheis."

Same thing for Power Streering, the most understressed system on a
car. Mine I have to actually worry about - but only because the truck
has a Hydrovac brake booster, and failure is not an appealing option.
A good way to judge the honesty level of a shop IMNSHO is to have a
frank talk with the mechanic and/or Service Writer, and tell them you
know these "Profit Center" services are all mostly worthless -
radiator backflushing is the only reasonable one because radiators
don't come apart for cleaning anymore.

If they "drank the Flushing Kool-Aid" and keep insisting they are
all totally needed and highly valuable services "And we're having a
Special on them this week!" you need to turn around and RUN.

They are putting earning an extra commission above integrity. What
else are they going to lie to you about?

-- Bruce --

The problem was a faulty ignition coil. They are sold in sets of 2. I got a new "Bank 2 Ignition
Coil Cassette". Also had them do the "BG- INJ W/TB Service" which is touted to effectively clean
fuel injectors, intake manifold ports, intake valve and combustion chamber. Supposedly they open
the fuel line and feed the engine from a cannister of whatever the cleaning agent is.

Thanks for all the hints, suggestions, etc, etc.

Bob Swinney


"Bruce L. Bergman" wrote in message
...
On Thu, 26 Feb 2009 08:58:21 -0600, "Robert Swinney"
wrote:

Thanx to all repliers. The car is now in the hands of local, (capable ?) Pontiac, Buick, GMC
dealer's service department. Business must be way off there. Right off the bat the service
advisor
tried to sell me some after-warranty "chemical" insurance when I explained the suspected injector
problem. I opted out of course.

Business IS way off, the New Car Sales side of the house at some
dealers has dropped 90% or more.

So the Service side of the house has been co-opted by the Gods Of
Profit to push many (usually of dubious utility) flushing services as
a form of prerventative maintenance. Radiator flushes, intake
cleaning, transmission flushes, final drive gears, oil system flushes,
power steering, brakes, air ducts in the Heater and Air
Conditioning...

You name a system, and they have a way to apply a vacuum cleaner to
your wallet to flush all the excess cash out of it.

Brake Bleeding $40 - Brake Flushing Service $129 for the same thing,
just done by an impressive looking machine that they wheel up to the
car and wave their hands while chanting "Ohwatta Foolheis."

Same thing for Power Streering, the most understressed system on a
car. Mine I have to actually worry about - but only because the truck
has a Hydrovac brake booster, and failure is not an appealing option.
A good way to judge the honesty level of a shop IMNSHO is to have a
frank talk with the mechanic and/or Service Writer, and tell them you
know these "Profit Center" services are all mostly worthless -
radiator backflushing is the only reasonable one because radiators
don't come apart for cleaning anymore.

If they "drank the Flushing Kool-Aid" and keep insisting they are
all totally needed and highly valuable services "And we're having a
Special on them this week!" you need to turn around and RUN.

They are putting earning an extra commission above integrity. What
else are they going to lie to you about?

-- Bruce --

On Thu, 26 Feb 2009 16:44:53 -0600, "Robert Swinney"
wrote:

The problem was a faulty ignition coil. They are sold in sets of 2. I got a new "Bank 2 Ignition
Coil Cassette". Also had them do the "BG- INJ W/TB Service" which is touted to effectively clean
fuel injectors, intake manifold ports, intake valve and combustion chamber. Supposedly they open
the fuel line and feed the engine from a cannister of whatever the cleaning agent is.

Thanks for all the hints, suggestions, etc, etc.

Bob Swinney

Thanks for the feed-back. I always wonder how things turned out.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

injector cleaning is pretty much a joke to real mechanics. Add a cleaner
like Chemtool 2-4 times a year to a full tank, and the only thing that can
get into your injectors is insoluable grit that passes thru the filter.

On Thu, 26 Feb 2009 16:44:53 -0600, "Robert Swinney"
wrote:

The problem was a faulty ignition coil. They are sold in sets of 2. I got a new "Bank 2 Ignition
Coil Cassette". Also had them do the "BG- INJ W/TB Service" which is touted to effectively clean
fuel injectors, intake manifold ports, intake valve and combustion chamber. Supposedly they open
the fuel line and feed the engine from a cannister of whatever the cleaning agent is.

Thanks for all the hints, suggestions, etc, etc.

Bob Swinney

The BG stuff works pretty good (and those coils ARE a common problem)

"Bruce L. Bergman" wrote in message
.. .
On Thu, 26 Feb 2009 08:58:21 -0600, "Robert Swinney"
wrote:

Thanx to all repliers. The car is now in the hands of local, (capable ?) Pontiac, Buick, GMC
dealer's service department. Business must be way off there. Right off the bat the service
advisor
tried to sell me some after-warranty "chemical" insurance when I explained the suspected injector
problem. I opted out of course.

Business IS way off, the New Car Sales side of the house at some
dealers has dropped 90% or more.

So the Service side of the house has been co-opted by the Gods Of
Profit to push many (usually of dubious utility) flushing services as
a form of prerventative maintenance. Radiator flushes, intake
cleaning, transmission flushes, final drive gears, oil system flushes,
power steering, brakes, air ducts in the Heater and Air
Conditioning...

You name a system, and they have a way to apply a vacuum cleaner to
your wallet to flush all the excess cash out of it.

Brake Bleeding $40 - Brake Flushing Service $129 for the same thing,
just done by an impressive looking machine that they wheel up to the
car and wave their hands while chanting "Ohwatta Foolheis."

Same thing for Power Streering, the most understressed system on a
car. Mine I have to actually worry about - but only because the truck
has a Hydrovac brake booster, and failure is not an appealing option.
A good way to judge the honesty level of a shop IMNSHO is to have a
frank talk with the mechanic and/or Service Writer, and tell them you
know these "Profit Center" services are all mostly worthless -
radiator backflushing is the only reasonable one because radiators
don't come apart for cleaning anymore.

If they "drank the Flushing Kool-Aid" and keep insisting they are
all totally needed and highly valuable services "And we're having a
Special on them this week!" you need to turn around and RUN.

They are putting earning an extra commission above integrity. What
else are they going to lie to you about?

-- Bruce --

On Thu, 26 Feb 2009 16:44:53 -0600, "Robert Swinney"
wrote:

The problem was a faulty ignition coil. They are sold in sets of 2. I got a new "Bank 2 Ignition
Coil Cassette". Also had them do the "BG- INJ W/TB Service" which is touted to effectively clean
fuel injectors, intake manifold ports, intake valve and combustion chamber. Supposedly they open
the fuel line and feed the engine from a cannister of whatever the cleaning agent is.

Thanks for all the hints, suggestions, etc, etc.

For precision's sake,they aren't "sold in sets of two" - one coil
does two cylinders.

The cylinder that is in compression stroke approaching TDC fires,
and the other cylinder is on the exhaust stroke and the spark is
wasted.

-- Bruce --

Bruce L. Bergman wrote:

Business IS way off, the New Car Sales side of the house at some
dealers has dropped 90% or more.


Not just them. Walmart is where I go for an oil change in the winter. The first thing
that burns my ass is that I only use 4 quarts nad the cost is figured around 5.

They used to haved a no frills, oil and filter change but the last time I stopped in it
was one price only. The 'deluxe' package. I don't need my car vaccumed, the driver side
floor tends to be a frozen mass of ice this time of year. Pasenger side generally has
mail, tools I transport back and forth and the back is the same way as far as tools.

They ask the typical questions, do you want to have your air filter replaced if it needs
it, do you want your wipers replaced if it needs it. Must be a lot of suckers for that
one.

Then they tell me my battery is bad. I just bought one from them two months ago. If I
had replaced the starter first, I'd still be running the OEM from 2001.

The topper was that they told me my tires were down to 4/32 and need replacing. Maybe
over the wear bars but no where else.

Oh yes, they tried to sell me injector cleaner also.

I gotta get either the lathe or the bridgeport moved so I can get a car into the garage to
diy it in winter. Each blocks one bay. (metal working content)

Wes

On Thu, 26 Feb 2009 18:06:18 -0500, Wes wrote:

Bruce L. Bergman wrote:

Business IS way off, the New Car Sales side of the house at some
dealers has dropped 90% or more.


Not just them. Walmart is where I go for an oil change in the winter. The first thing
that burns my ass is that I only use 4 quarts nad the cost is figured around 5.

They used to haved a no frills, oil and filter change but the last time I stopped in it
was one price only. The 'deluxe' package. I don't need my car vaccumed, the driver side
floor tends to be a frozen mass of ice this time of year. Pasenger side generally has
mail, tools I transport back and forth and the back is the same way as far as tools.

They ask the typical questions, do you want to have your air filter replaced if it needs
it, do you want your wipers replaced if it needs it. Must be a lot of suckers for that
one.

Then they tell me my battery is bad. I just bought one from them two months ago. If I
had replaced the starter first, I'd still be running the OEM from 2001.

The topper was that they told me my tires were down to 4/32 and need replacing. Maybe
over the wear bars but no where else.

Oh yes, they tried to sell me injector cleaner also.

I gotta get either the lathe or the bridgeport moved so I can get a car into the garage to
diy it in winter. Each blocks one bay. (metal working content)

Wes
Go to a MECHANIC for crying out loud!!! What do you expect from a
MASS MARKETER like WALLMART????????????????????????????????????????

On Thu, 26 Feb 2009 14:07:58 -0800, Bruce L. Bergman
wrote:

On Thu, 26 Feb 2009 08:58:21 -0600, "Robert Swinney"
wrote:

Thanx to all repliers. The car is now in the hands of local, (capable ?) Pontiac, Buick, GMC
dealer's service department. Business must be way off there. Right off the bat the service advisor
tried to sell me some after-warranty "chemical" insurance when I explained the suspected injector
problem. I opted out of course.

Business IS way off, the New Car Sales side of the house at some
dealers has dropped 90% or more.

So the Service side of the house has been co-opted by the Gods Of
Profit to push many (usually of dubious utility) flushing services as
a form of prerventative maintenance. Radiator flushes, intake
cleaning, transmission flushes, final drive gears, oil system flushes,
power steering, brakes, air ducts in the Heater and Air
Conditioning...

You name a system, and they have a way to apply a vacuum cleaner to
your wallet to flush all the excess cash out of it.

Brake Bleeding $40 - Brake Flushing Service $129 for the same thing,
just done by an impressive looking machine that they wheel up to the
car and wave their hands while chanting "Ohwatta Foolheis."

Same thing for Power Streering, the most understressed system on a
car. Mine I have to actually worry about - but only because the truck
has a Hydrovac brake booster, and failure is not an appealing option.
A good way to judge the honesty level of a shop IMNSHO is to have a
frank talk with the mechanic and/or Service Writer, and tell them you
know these "Profit Center" services are all mostly worthless -
radiator backflushing is the only reasonable one because radiators
don't come apart for cleaning anymore.

If they "drank the Flushing Kool-Aid" and keep insisting they are
all totally needed and highly valuable services "And we're having a
Special on them this week!" you need to turn around and RUN.

They are putting earning an extra commission above integrity. What
else are they going to lie to you about?

-- Bruce --
They should not be "wholesaled" as a profit center - but they are a
usefull tool in many cases. Would you like a $45 Power Stearing flush
to see if we can quiet down that nasty whine, or should we just go
ahead and throw a $300 rack and a $200 pump (and another 250 bucks
worth of hoses) at it right away? Oh, and by the way, the labour to
replace the pump and rack is $700.And you'll still need the fluid too.

Durn right I'll try the flush and the $8 bottle of conditioner.

Brake bleeding or brake flush? Depends how well the system will be
bled for $40. Will ALL of the fluid be changed? How about the ABS
accumulators? A proper brake flush will remove the moisture
contaminated and heat deteriorated fluid from the system in it's
entirety - and replace it with fresh clean fluid.

IF the fluid is "changed" every 48 months by a proper bleeding, the
"hot dog" flush is not required. How many vehicles EVER get a brake
bleed unless a component goes bad, REQUIRING the system to be
opened???? They should. And the car will last longer with less
problems if all the "recommmended services" are done at or before the
recommended interval.

Ever price out replacing all flex lines, all caliprs, master cyl and
ABS assembly on a 3 year old car??? I see cars go to the scrapyard
because "they just are not worth repairing" whn they need a complete
brake job (abs problems) and the steering rack is "notchy"

THAT is criminal.
Selling proper maintenance is not.
Overselling IS - but so is "purposeful neglect"

THAT is criminal.
Selling proper maintenance is not.

There is a reason that Mercedes shops charge a lot for a major service. It
takes most of the day, and there are many parts designed to be serviced at
specific intervals. Fail to do so and it will cost you big. Do it on
schedule and the car will last. My 1963 190Dc went for 774,000 miles with no
engine work. Never had the head or oil pan off. It finally needed an
overhaul and got scrapped. My 82 300TD is at 250,000 and runs great. My 82
VW Jetta diesel is at about the same, getting tired though. Carbureted cars
didnt usually make it to 200,000 miles.

Chrysler got into big trouble when brake systems failed and there was no
interval recommended to change the fluid. For some reason American car
makers tend to recommend under-maintenance. I don't understand why BMW
thinks steering fluid (Dexron ATF) should be replaced at 30,000 miles and
Ford doesn't think you need to change it at all.

A BMW will idle bad if the dipstick isn't seated in the tube. A spark plug
with 36,000 miles on it should be bad. A rat's nest in the intake doesn't
filter air very well.
This is a machining NG, but there are some guys here who know a lot.
Answering a question online like the OP's is usually futile, unless he gives
full symptoms, maintenance history, and tells us what he has checked. Even
then it's a crapshoot, I cant hear it, so my wild guess is likely to be
wrong.

--
Stupendous Man,
Defender of Freedom, Advocate of Liberty