Rough Idle
Thread Starter
1st Gear
Joined: Sep 2003
Posts: 1
Likes: 0
From: Raleigh NC
Rough Idle
I have a 2001 automatic with 33K miles, and it is idling much rougher that I would have expected. It is especially bad after it has been driven for a while (over 30min or so). When you are stopped, (both in drive and park) it rumbles pretty heavily to the point it shakes you around a bit. I've taken it to the dealership several times and they say there's nothing they can do since it isnt producing and engine codes. I have called Chevy cust service and their response is "sometimes vettes just idle rough like that". Needless to say I am a bit disappointed that they feel its acceptable for their high perf. flagship to run like an old tractor. I guarantee you that the Germans and Japs dont have that type of attitude. Has anyone else experience this type of problem? Anys suggestions on what it might be?
Le Mans Master
Joined: Aug 2001
Posts: 7,064
Likes: 18
From: Arizona
Re: Rough Idle (dan_miller5150)
check your air bridge.. if you are getting unregulated air in the manifold it will cause it to run rough.... I bet it is somewhere between your manifold and the air filter.
Drifting
Joined: Jan 2002
Posts: 1,498
Likes: 3
From: Sacramento CA
Re: Rough Idle (dan_miller5150)
Welcome to the forum!
Yes the vette does shake a bit at idle. This is normal for the car, unless it is so bad that you think it is going to die. You can also have the idle raised by LS1 edit.
[Modified by Jackal, 12:16 PM 1/9/2004]
Yes the vette does shake a bit at idle. This is normal for the car, unless it is so bad that you think it is going to die. You can also have the idle raised by LS1 edit.
[Modified by Jackal, 12:16 PM 1/9/2004]
Advanced
Joined: Sep 2003
Posts: 53
Likes: 0
From: Norcross, Ga
Re: Rough Idle (dan_miller5150)
My vette shakes at idle also. I have been told this is due to the cam. If you ever notice pushrod cars with a lot of cam idle very erratic. The stock cam I believe is a compremise and setup just before the heavy shake of a higher performance cam. I don't think it is a problem because the LSx is that type of torque driven engine. Asian and European car are overhead cam and do not work the same and really don't produce the power without turbos and that is another story. :cheers:
[Modified by 57xray, 2:39 PM 1/9/2004]
[Modified by 57xray, 2:39 PM 1/9/2004]
Le Mans Master
Joined: Oct 1999
Posts: 8,205
Likes: 40
From: Tucson AZ
Re: Rough Idle (dan_miller5150)
Welcome to the Forum! Yes, SOME roughness is characteristic of the LS1 engine, but yours sounds much worse than that. Check the spark plug wires, plugs (gap, or cracked insulator), air leaks, as mentioned above, and consider doing a decarbonization proceedure. Some have reported a much better idle after cleaning out the carbon deposits. Good luck.
:)
:)
Le Mans Master
Joined: Nov 2003
Posts: 8,004
Likes: 250
From: Tampa Fl
St. Jude Donor '12-'13-'14
Re: Rough Idle (dan_miller5150)
welcome to the forum
Put it a huge cam in that bad boy, and you'll at least have an excuse.
im turning onto a guy I hate. I hate when guys post dumb remarks to questions :nonod: :nonod: :nonod: :nonod: :nonod:
Put it a huge cam in that bad boy, and you'll at least have an excuse.
im turning onto a guy I hate. I hate when guys post dumb remarks to questions :nonod: :nonod: :nonod: :nonod: :nonod:
Pro
Joined: Jan 2004
Posts: 675
Likes: 0
From: FT Bragg North Carolina
Re: Rough Idle (phils C5 vette)
I would defintely check the spark plugs, both my 97 and my 99 were missing several of the factory platinum tips making the gaps to vary between .57-.70 thousands. I was missing three off my 99 after only 19K!!!! I replaced them with NGK TR55's and it did idle a lot smoother. :thumbs:
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Burning Brakes
Joined: Dec 2000
Posts: 993
Likes: 5
From: Cincinnati Ohio
Re: Rough Idle (dan_miller5150)
dan_miller5150,
I replaced the original spark plugs with replacement Delco plugs in my 1999 C5 coupe (A4) at 30,000 miles and the car idled much smoother. Chevrolet states that the spark plugs can last up to 100,000 miles - don't believe it.
Change your plugs (easy) and see if that smooths the idle out. Good luck.
I replaced the original spark plugs with replacement Delco plugs in my 1999 C5 coupe (A4) at 30,000 miles and the car idled much smoother. Chevrolet states that the spark plugs can last up to 100,000 miles - don't believe it.
Change your plugs (easy) and see if that smooths the idle out. Good luck.
Team Owner
Joined: Sep 2002
Posts: 30,578
Likes: 4,612
From: Bonita Springs, Florida
Re: Rough Idle (1999 White C5 Coupe)
:iagree:
I would check the spark plugs. If they need replacing you might as well replace the wires with some low resistance wires such as MSD.
Have you noticed a decrease in your MPG's?
Also, to be thorough, check the airbridge.
Chevrolet states that the spark plugs can last up to 100,000 miles - don't believe it.
Change your plugs (easy) and see if that smooths the idle out. Good luck.
Change your plugs (easy) and see if that smooths the idle out. Good luck.
Have you noticed a decrease in your MPG's?
Also, to be thorough, check the airbridge.
Le Mans Master
Joined: Dec 2003
Posts: 5,561
Likes: 448
From: Atlanta metro Ga.
Re: Rough Idle (dan_miller5150)
I have a 2001 automatic with 33K miles, and it is idling much rougher that I would have expected. It is especially bad after it has been driven for a while (over 30min or so). When you are stopped, (both in drive and park) it rumbles pretty heavily to the point it shakes you around a bit. I've taken it to the dealership several times and they say there's nothing they can do since it isnt producing and engine codes. I have called Chevy cust service and their response is "sometimes vettes just idle rough like that". Needless to say I am a bit disappointed that they feel its acceptable for their high perf. flagship to run like an old tractor. I guarantee you that the Germans and Japs dont have that type of attitude. Has anyone else experience this type of problem? Anys suggestions on what it might be?
Racer
Joined: Oct 2002
Posts: 266
Likes: 0
From: San Angelo Texas
Re: Rough Idle (dan_miller5150)
If it were anything out of the ordinary then the computer would more than likely let you know. LS1's just idle rough. That is my guess without actually hearing the car, but if you still have doubts then keep asking. You know your car better than anyone else does. :cheers:
Team Owner
Joined: Mar 1999
Posts: 28,753
Likes: 9
From: San Jose/Bear Valley CA
CA Events Coordinator
Re: Rough Idle (dan_miller5150)
Replace your plugs and wires and then see how it runs. If it still has a miss, then check your coils with a timing light to see if they all have a steady beat. I had a bad coil that was not working correctly, the car missed like hell for 3 years and it didnt throw a code. Once we replaced the bad coil, the car ran very smooth. If all of those parts are good, your optispark unit could be bad as well.
VR :cheers:
VR :cheers:
