2002 coupe idle "stumble"
Thread Starter
4th Gear
Joined: Jan 2002
Posts: 4
Likes: 0
From: Martinez CA
2002 coupe idle "stumble"
Hi ya'll,
Just traded up from a 96 Impala SS, great car......but the C5...WOW!! what a ride!!
I have just over 800 bone stock miles. I'm noticing a stumble or a slight shaking @ idle, especially once warmed up. (reminds of a dog gently wagging it's tail)
Is this unusual or anything to be concerned about?
:flag
Just traded up from a 96 Impala SS, great car......but the C5...WOW!! what a ride!!
I have just over 800 bone stock miles. I'm noticing a stumble or a slight shaking @ idle, especially once warmed up. (reminds of a dog gently wagging it's tail)
Is this unusual or anything to be concerned about?
:flag
Team Owner
Joined: Apr 2001
Posts: 54,204
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From: S.W. Ohio. . . . . . NRA Life Member
Re: 2002 coupe idle "stumble" (Hugh)
My '02 does something similar... more like a random shake at idle (like it had a radical cam); but the engine runs perfect otherwise.
Team Owner
Joined: Mar 1999
Posts: 28,753
Likes: 9
From: San Jose/Bear Valley CA
CA Events Coordinator
Re: 2002 coupe idle "stumble" (Hugh)
I had the same problem on my car. I took it back to different Dealership's many times to have it fixed and they said "nothing was wrong". I replaced the plugs and wires 2 times and it still ran the same. 2.9 years later we found out it was a bad coil. Now the car runs like a champ. :eek:
vetterdstr :cheers:
vetterdstr :cheers:
Team Owner
Joined: Mar 1999
Posts: 28,753
Likes: 9
From: San Jose/Bear Valley CA
CA Events Coordinator
Re: 2002 coupe idle "stumble" (JMs99C5)
The coils are located under the Plastic Covers on each side of the engine. Each cylinder has a coil. If your car is running badly like mine did...you can change the Plugs and wires first. Then if it does not run correctly you can check the spark with a hand held inductive pick up device to check the coils. I talked at length about this and even posted Dyno Runs showing the miss on my car... I cant seem to find the post. :(
vetterdstr :cheers:
vetterdstr :cheers:
Melting Slicks
Joined: Jan 2001
Posts: 2,361
Likes: 0
From: Sugar Land, TX USA
Re: 2002 coupe idle "stumble" (JMs99C5)
Where is the coil located???? My 2002 has that same rumble at idle.
I have a slight rumble at idle on my 01. Almost like a very faint "miss" but,
my coils are fine. New plugs and wires as well. He!!, I don't know.
I did see a friends Z06 idle smooth out considerable after installing an
aftermarket air bridge. That really BIG one from LAPD.
Another friend found his MAF very dirty and the idle lump disappeared
after cleaning it.
Wish I had the answer for mine, cuzzz it bugs me :cuss
Melting Slicks
Joined: Jan 2001
Posts: 2,361
Likes: 0
From: Sugar Land, TX USA
Re: 2002 coupe idle "stumble" (vetterdstr)
Then if it does not run correctly you can check the spark with a hand held inductive pick up device to check the coils.
time and do not know DIC about auto electrical systems.
thanks
Team Owner
Joined: Mar 1999
Posts: 28,753
Likes: 9
From: San Jose/Bear Valley CA
CA Events Coordinator
Re: 2002 coupe idle "stumble" (MySea5)
The Name of this unit they used to find the bad coil with is called:
Enerpac Automotive Pro, Tru Spark Ignition Firing Indicator.
It is a small hand held unit that is about 2.5 times thicker than a Ball Point Pen. It also has a dial on it to dial in the sensitivity of the unit. What you do with it is while the car is running, touch the end of the handheld unit to the spark plug wire and the little red light at the other end of the unit will flash red each time the coil fires. When we did this to my car each coil had a steady beat except for #7 which skipped beats. You can buy a unit like this off of any Mechanic Tool Truck that visits local auto shops and the like for around $20.
vetterdstr :cheers:
Enerpac Automotive Pro, Tru Spark Ignition Firing Indicator.
It is a small hand held unit that is about 2.5 times thicker than a Ball Point Pen. It also has a dial on it to dial in the sensitivity of the unit. What you do with it is while the car is running, touch the end of the handheld unit to the spark plug wire and the little red light at the other end of the unit will flash red each time the coil fires. When we did this to my car each coil had a steady beat except for #7 which skipped beats. You can buy a unit like this off of any Mechanic Tool Truck that visits local auto shops and the like for around $20.
vetterdstr :cheers:
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Team Owner
Joined: Jul 2001
Posts: 21,396
Likes: 1,011
From: Various places in Southern California.
Re: 2002 coupe idle "stumble" (Hugh)
Almost every C5 I've been in, including mine, has that very faint shake at idle. It almost feels as if there is a weak spark every five or ten seconds. If this is what you're experiencing, I wouldn't worry about it.
As the dealers like to say, "They all do that." :rolleyes:
As the dealers like to say, "They all do that." :rolleyes:
Team Owner
Joined: Mar 1999
Posts: 28,753
Likes: 9
From: San Jose/Bear Valley CA
CA Events Coordinator
Re: 2002 coupe idle "stumble" (AdamB)
My Car had an all out miss at all Rpm's since the day it was new. The Dealership told me they all run that way too. :rolleyes: The Dyno Runs even had gaps in them from the miss. :eek:
IF that is what you are feeling check the coils, plugs and wires. Here is a Dyno after the Coil install with the additional Dyno done a month before.
If you want to believe what the Dealership is telling you "that Every C5 runs badly" then dont do anything at all. :nopity
vetterdstr :smash:
IF that is what you are feeling check the coils, plugs and wires. Here is a Dyno after the Coil install with the additional Dyno done a month before.
If you want to believe what the Dealership is telling you "that Every C5 runs badly" then dont do anything at all. :nopity
vetterdstr :smash:
Melting Slicks
Joined: Aug 2000
Posts: 2,248
Likes: 1
From: Newland US
Re: 2002 coupe idle "stumble" ()
The Name of this unit they used to find the bad coil with is called:
Enerpac Automotive Pro, Tru Spark Ignition Firing Indicator.
It is a small hand held unit that is about 2.5 times thicker than a Ball Point Pen. It also has a dial on it to dial in the sensitivity of the unit. What you do with it is while the car is running, touch the end of the handheld unit to the spark plug wire and the little red light at the other end of the unit will flash red each time the coil fires. When we did this to my car each coil had a steady beat except for #7 which skipped beats. You can buy a unit like this off of any Mechanic Tool Truck that visits local auto shops and the like for around $20.
vetterdstr :cheers:
Enerpac Automotive Pro, Tru Spark Ignition Firing Indicator.
It is a small hand held unit that is about 2.5 times thicker than a Ball Point Pen. It also has a dial on it to dial in the sensitivity of the unit. What you do with it is while the car is running, touch the end of the handheld unit to the spark plug wire and the little red light at the other end of the unit will flash red each time the coil fires. When we did this to my car each coil had a steady beat except for #7 which skipped beats. You can buy a unit like this off of any Mechanic Tool Truck that visits local auto shops and the like for around $20.
vetterdstr :cheers:
Do you happen to know if the tool you describe above is more sensitive than just using an old inductive timing light? I already have one of those, for setting timing adjustment before computer controlled timing came along.
Thanks.
Mark
Team Owner
Joined: Mar 1999
Posts: 28,753
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From: San Jose/Bear Valley CA
CA Events Coordinator
Re: 2002 coupe idle "stumble" () (MDT)
You could use a timing light... I think this unit is much better though. You can dial out interference and interpret the information much better.
vetterdstr
vetterdstr
☠☣☢ Semper Ebrius ☢☣☠
Joined: Jun 2001
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From: Virginia
Cruise-In IV-V-VI-VII Veteran
St. Jude's Donor '06
Re: 2002 coupe idle "stumble" (Duck916)
Almost every C5 I've been in, including mine, has that very faint shake at idle. It almost feels as if there is a weak spark every five or ten seconds. If this is what you're experiencing, I wouldn't worry about it.
As the dealers like to say, "They all do that."
As the dealers like to say, "They all do that."
Drifting
Joined: Mar 2001
Posts: 1,993
Likes: 0
From: Joliet IL
Re: 2002 coupe idle "stumble"
I would change the plugs as the first step. I recently had mine changed out and found that seven of the plugs were gapped at .055" and one was gapped at .042". :eek: I replaced the wires at the same time and did notice a improved idle after everything was said and done.
:cheers:
:cheers:
Racer
Joined: Jun 2001
Posts: 323
Likes: 0
From: Atlanta GA
Re: 2002 coupe idle "stumble" (Hugh)
I remeber when I was at the dealership with my '96 T/A (OBDII) that they had a thing they could plug in and were able to pull out the misfires on cylinders right out of the computer. Don't know if the LS1's can do this also though.
Ted
PS - I think I remember the tech saying something about how it uses the crank shaft sensor to sense the pulses of each cylinder firing, made sense at the time. I watched the read out to see that cylinder #5 was missing. Turned out somebody had put the incorrect spark plug in this cylinder. (I was getting the car inspected for I was looking into buying it)
Ted
PS - I think I remember the tech saying something about how it uses the crank shaft sensor to sense the pulses of each cylinder firing, made sense at the time. I watched the read out to see that cylinder #5 was missing. Turned out somebody had put the incorrect spark plug in this cylinder. (I was getting the car inspected for I was looking into buying it)
Melting Slicks
Joined: Aug 2000
Posts: 2,248
Likes: 1
From: Newland US
Re: 2002 coupe idle "stumble" (Mike Mercury)
It comes from having a cross-plane V8.
Scissors; would you please expand on that?
Scissors; would you please expand on that?
Try this link: http://www.fortunecity.com/silversto...ne/smooth4.htm
vetterdstr,
OK on your answer about using the timing light...It's what I've used often in the past. :)
Good luck.
Mark
Burning Brakes
Joined: Oct 2001
Posts: 770
Likes: 0
From: DYER IN
Re: 2002 coupe idle "stumble" (Hugh)
I, Myself have had the same type of problems on my 02
I dont know what it is but using the suto tap i didnt notice
any misfires or coil problems.... I did however notice depending
on the type of gasoline you use it will make a difference, but
since then i changed to the hall tech cold air intake and change
the spark plugs (the gaps were all different - from the dealership
<~~~~ even heard a few people talk about it, so i checked) I
have not noticed the problem anymore. Oh and now i have 4500
miles on her.
just my .02
I dont know what it is but using the suto tap i didnt notice
any misfires or coil problems.... I did however notice depending
on the type of gasoline you use it will make a difference, but
since then i changed to the hall tech cold air intake and change
the spark plugs (the gaps were all different - from the dealership
<~~~~ even heard a few people talk about it, so i checked) I
have not noticed the problem anymore. Oh and now i have 4500
miles on her.
just my .02
☠☣☢ Semper Ebrius ☢☣☠
Joined: Jun 2001
Posts: 83,301
Likes: 4
From: Virginia
Cruise-In IV-V-VI-VII Veteran
St. Jude's Donor '06
Re: 2002 coupe idle "stumble" (MDT)
Thanks for posting that link, MDT.
You:
A. Saved me from having to type up an explanation.
B. Showed me a new site that I'll have to save to my hard drive for future reading.
[Modified by Scissors, 4:54 PM 1/4/2002]
You:
A. Saved me from having to type up an explanation.
B. Showed me a new site that I'll have to save to my hard drive for future reading.
[Modified by Scissors, 4:54 PM 1/4/2002]