I don't see a newsgroups available for Chevy cars. I have posted here
before and frequently read items from this newsgroup. I'm looking for a
"second opinion" about a dealer's diagnosis. I took my '04 Impala (3800
V-6) to the dealer this morning due to a faulty tach reading. Not a major
issue, but I did purchase an extended warranty which covered this repair. I
was thinking that they may replace a faulty stepper motor, which seems to be
a common problem. The dealer advised that I would need a new dash cluster,
which would also be covered - $100 deductible payment only. Anyway, I also
mentioned that about the same time that the tach reading failed, I also
noticed that when the vehicle sat overnight, the first time you stepped on
the accelerator it felt like it was stuck. You had to push the pedal a
little harder and finally the car would go. After that everything was
fine - you could take off smoothly.
The service writer quickly stated that I needed the fuel injector/throttle
body cleaning service - a $129 charge to cure this problem. Apparently the
technician who looked at the dash felt this was the case also. I'm
wondering if the faulty tach reading is related to this throttle issue.
Could there be any possible correlation or does the need for a throttle body
cleaning sound legitimate? The car has nearly 50,000 miles on it. The
service writer stated I should be noticing a severe drop in gas mileage. A
fair amount of my travel is on the highway. On a recent 300 mile trip on a
cold windy day, I got 27 miles/gallon in city/highway driving. I would
consider that to be appropriate for the conditions, considering the crappy
winter blend gas we have here in northern IL. I think the mileage ratings
for this car were 30mpg on the highway. Any thoughts and/or constructive
comments are appreciated. Thanks!
Meat Plow - 14 Mar 2008 19:04 GMT
> I don't see a newsgroups available for Chevy cars. I have posted here
> before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 23 lines]
> think the mileage ratings for this car were 30mpg on the highway. Any
> thoughts and/or constructive comments are appreciated. Thanks!
It's a problem in the 03 Vortec 4.2 from what I've read. I'll have to
clean mine this spring weather permitting as it is a little sluggish @ 60k
miles.
ScottM - 14 Mar 2008 19:09 GMT
The tach has nothing the do with the throttle body.
they are trying to sell you a very profitable "cleaning". I seriously doubt
a dirtly TB would cause that much sticking of the throttle, HIGHLY unlikely.
a sticking pedal usually is cable or pedal related. could be cruise related
too I guess. That car is most likely injected with injectors at each
cylinder so an injector cleaning wont do crap either.
did it only stick once? Does it do it every morning?
Eiter way unless you have money to burn I would pass on the injector
cleaning at 50k.
He probably tells everyone they need that service. ($commision$)
What about a stepper motor?
Oh, there is a recall on 03/04 chevy pickups with bad clusters I wonder if
the Impala has a similar problem....
>I don't see a newsgroups available for Chevy cars. I have posted here
>before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 23 lines]
> think the mileage ratings for this car were 30mpg on the highway. Any
> thoughts and/or constructive comments are appreciated. Thanks!
Meat Plow - 14 Mar 2008 20:25 GMT
> The tach has nothing the do with the throttle body.
>
[quoted text clipped - 16 lines]
> Oh, there is a recall on 03/04 chevy pickups with bad clusters I wonder if
> the Impala has a similar problem....
I'm going to guess since "stepper motor was used" in the wording that the
04 Impala 3800 throttle is fly by wire like my 03 4.2 Vortec. This would
eliminate any "sticky pedal/cable" problem and pretty much isolate it to
either the stepper or deposits inside the TB.
>>I don't see a newsgroups available for Chevy cars. I have posted here
>>before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 24 lines]
>> were 30mpg on the highway. Any thoughts and/or constructive comments
>> are appreciated. Thanks!
ScottM - 15 Mar 2008 18:33 GMT
>> The tach has nothing the do with the throttle body.
>>
[quoted text clipped - 22 lines]
> eliminate any "sticky pedal/cable" problem and pretty much isolate it to
> either the stepper or deposits inside the TB.
Yes but.....Why would the pedal be hard to push?????
I've never worked on a "fly by wire" system, doesn't that mean there isn't a
cable to stick?
he said the *pedal* was stuck. Heck, it coulda been the floor mat too.
>>>I don't see a newsgroups available for Chevy cars. I have posted here
>>>before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 24 lines]
>>> were 30mpg on the highway. Any thoughts and/or constructive comments
>>> are appreciated. Thanks!
Meat Plow - 16 Mar 2008 21:26 GMT
>>> The tach has nothing the do with the throttle body.
>>>
[quoted text clipped - 26 lines]
> a "fly by wire" system, doesn't that mean there isn't a cable to stick?
> he said the *pedal* was stuck. Heck, it coulda been the floor mat too.
He may have referring to feeling like the pedal was stuck as a lag in
engine response. I've noticed this on my 03, 4.2L and that's why I took
it that way. The stepper would be mounted directly on the TB (assumptiuon).
Although I haven't looked I would assume that the end of the
pedal is fitted with some kind of potentiometer or an LED or HAL device
to transmit the pedal motion to the ECU. It would be possible for the
pedal to bind somehow but the stuck pedal issue to me is a lag in the
engine when the pedal was pressed.
My 4.2L Vortec i6 had a pretty good lag in it after I replaced the
battery. I think I spiked the ECU when I was reattaching the - cable and
touched it to the battery pad and the alarm went off :) Naturally I jumped
and the connection sparked. After that when I ran the air or defrost the
compressor would kick in and kill the engine (at idle) or idle up and down
until it died. The ECU wasn't adjusting the idle quick enough to make up
for the additional load the compressor put on the motor. Someone lurking
here chimed in with "clean the TB" but after a couple days the ECU being a
"learning" ECU relearned when I had wiped out (another assumption) when I
spiked it. Now it idles ok and I will clean the TB this spring when it
warms up, don't have a heated garage and there looks like a lot of junk I
have to remove to get to the TB. I might even price out a new stepper and
slap that in just because I'm there. Also need a new serp belt at 61k it's
a little squeaky.
>>>>I don't see a newsgroups available for Chevy cars. I have posted here
>>>>before and frequently read items from this newsgroup. I'm looking for
[quoted text clipped - 26 lines]
>>>> I think the mileage ratings for this car were 30mpg on the highway.
>>>> Any thoughts and/or constructive comments are appreciated. Thanks!
NickySantoro - 15 Mar 2008 00:11 GMT
>I don't see a newsgroups available for Chevy cars.
http://www.automotiveforums.com
Certainly - 15 Mar 2008 05:32 GMT
> I don't see a newsgroups available for Chevy cars. I have posted here
> before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 23 lines]
> for this car were 30mpg on the highway. Any thoughts and/or constructive
> comments are appreciated. Thanks!
On google groups try alt.autos.gm for cars. Throttle deposits can
cause a sticking throttle plate, typically when cold and the deposits
are gummy. If you have the aptitude, a $4.99 can of carb cleaner and a
shop towel will save you about a $124 bucks. Remove the air inlet
snorkel and open the throttle plate, spray liberally the back side of
the plate, and the bore, wipe with rag and done. The only hitch is if
the mass airflow sensor is mounted right on the throttle body, then it
would need removed. I don't know why you would notice a severe drop in
mpg, that don't make sense. If the tach jumps erattically, I would
agree with the cluster issue. The dealer should have a scan tool that
can perform output tests which would include a gauge sweep test on the
ipc. That can be one way to diagnose it, other than a shot from the
hip.
Gerald
Kevin - 15 Mar 2008 15:14 GMT
I used to clean the throttle body on my '95 Yukon once a year. It looked
like new when done using a can of spray carb cleaner. Never had any problems
with that truck or engine. Can't say that about any of the newer Vortec
engines...... :-( They have more power for sure, but they also have
issues.
On Mar 14, 8:39 am, "Gary Picha" <chevy2...@comcast.net> wrote:
> I don't see a newsgroups available for Chevy cars. I have posted here
> before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 26 lines]
> for this car were 30mpg on the highway. Any thoughts and/or constructive
> comments are appreciated. Thanks!
On google groups try alt.autos.gm for cars. Throttle deposits can
cause a sticking throttle plate, typically when cold and the deposits
are gummy. If you have the aptitude, a $4.99 can of carb cleaner and a
shop towel will save you about a $124 bucks. Remove the air inlet
snorkel and open the throttle plate, spray liberally the back side of
the plate, and the bore, wipe with rag and done. The only hitch is if
the mass airflow sensor is mounted right on the throttle body, then it
would need removed. I don't know why you would notice a severe drop in
mpg, that don't make sense. If the tach jumps erattically, I would
agree with the cluster issue. The dealer should have a scan tool that
can perform output tests which would include a gauge sweep test on the
ipc. That can be one way to diagnose it, other than a shot from the
hip.
Gerald
Jon - 15 Mar 2008 13:41 GMT
Get a can of carb cleaner and do the job yourself. Also it would not hurt
to put in some fuel system cleaner to get to the parts in the fuel system.
My vehicle has a sensor on the pedal, there is no cable or arm going to the
throttle body. The throttle body has the receiver for the pedal position.
For fuel system cleaner use Techroline, as it has more of the actual
chemical that cleans your fuel injection system than any other cleaner out
there.
Jon
NW Chicago burbs
>I don't see a newsgroups available for Chevy cars. I have posted here
>before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 23 lines]
> think the mileage ratings for this car were 30mpg on the highway. Any
> thoughts and/or constructive comments are appreciated. Thanks!
PerfectReign - 17 Mar 2008 16:54 GMT
> I don't see a newsgroups available for Chevy cars.
xposted to alt.autos.gm - that will get you some more answers...
> I have posted here
> before and frequently read items from this newsgroup. I'm looking for a
[quoted text clipped - 29 lines]
> for this car were 30mpg on the highway. Any thoughts and/or constructive
> comments are appreciated. Thanks!
Don't drive 120MPH? :P

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The Reverend Natural Light - 17 Mar 2008 20:09 GMT
> The service writer quickly stated that I needed the fuel injector/throttle
> body cleaning service - a $129 charge to cure this problem. Apparently the
> technician who looked at the dash felt this was the case also.
Service writers typically don't know very much about cars. You say
"sticky throttle", they try to sell you a throttle body cleaning
service. A work order is printed and handed to a mechanic who
performs a throttle body cleaning service.
Will it fix the problem? Maybe. Probably not. But they still got
your money.
(I can't take credit for this - read it on a post somewhere else.)
When they do that, take the work order and cross out "Perform throttle
body cleaning service". Write in "Fix sticky gas pedal". When
they're done, test drive the car. If the pedal is still sticky, don't
pay.
They should have the expertise and equipment to diagnose those
problems accurately without making you take a gamble. If course, they
deserve to get paid for that.