Notices
C5 General General C5 Corvette and C5 Z06 Discussion not covered in Tech

Uneven idle

Thread Tools
 
Search this Thread
 
Old May 9, 2007 | 07:15 AM
  #1  
Dudule's Avatar
Dudule
Thread Starter
Racer
 
Joined: Dec 2002
Posts: 289
Likes: 0
From: The wrong side of the Atlantic ocean
Default Uneven idle

I guys,

I've tried a 2001 C5 yesterday, the car is very nice, clean and meets all my expectation regarding the C5 that I'm looking for.
The only annoying stuff about this car is the uneven idle. It fells like the engine misfires at idle, it's not shon on the RPM gauge but you can feel it, and the owner told me that the spark plugs need to be changed (which he's gonna do before I'd buy the car), the car has 42000 miles.
Do you ever experienced the same and what do you think?
Thanks for your info
Greg
Reply
Old May 9, 2007 | 07:48 AM
  #2  
VinnyT's Avatar
VinnyT
Le Mans Master
15 Year Member
 
Joined: Jan 2007
Posts: 7,364
Likes: 6
From: Rocky Mount Virginia
Default

You will hear many answers to this. Plugs are good to 75000+ miles, but changing them wouldn't hurt. The LS1 motors will have the idle shudder to it. Many here will chime in with that. Drive it with the windows up, no radio and a smooth road if possible(a hill would be best). If it is misfiring you'll feel it. I think it is the notorious shudder. Nothing to worry about.
Reply
Old May 9, 2007 | 09:59 AM
  #3  
ptdrummer54's Avatar
ptdrummer54
Safety Car
 
Joined: Feb 2004
Posts: 4,208
Likes: 2
From: Rochester MN
CI 5-6-7-8 Veteran
St. Jude Donor '04-'05-'06-'07
NCM Ambassador
Default

I notcie it more after the engine warms up, but there is a slight roughness to the idle...
Reply
Old May 9, 2007 | 10:09 AM
  #4  
jbondfl's Avatar
jbondfl
Melting Slicks
Supporting Lifetime
15 Year Member
Veteran: Navy
 
Joined: Aug 2006
Posts: 2,866
Likes: 45
From: Tampa Bay, Go BUCS!!!Go Rays!!!Go Lightning!!!
St. Jude Donor '12-'13-'14
Default

Originally Posted by VinnyT
You will hear many answers to this. Plugs are good to 75000+ miles, but changing them wouldn't hurt. The LS1 motors will have the idle shudder to it. Many here will chime in with that. Drive it with the windows up, no radio and a smooth road if possible(a hill would be best). If it is misfiring you'll feel it. I think it is the notorious shudder. Nothing to worry about.


Let them change the plugs and test drive it again.
Did you notice if there is any rhythm to the "roughness"? It is possible there is a small cam in there.
Reply
Old May 9, 2007 | 11:37 AM
  #5  
Dudule's Avatar
Dudule
Thread Starter
Racer
 
Joined: Dec 2002
Posts: 289
Likes: 0
From: The wrong side of the Atlantic ocean
Default

Originally Posted by ptdrummer54
I notcie it more after the engine warms up, but there is a slight roughness to the idle...
That's true the engine ran roughly when warm (after the test drive) and I didn't notice any rythm in the roughless (but I'm not a musician )...
Reply
Old May 9, 2007 | 11:42 AM
  #6  
Humy's Avatar
Humy
Race Director
 
Joined: Aug 2001
Posts: 11,028
Likes: 5
From: Chicago (Naperville) IL
Default

oh yeah, mine idles rough, it because the engine run lean or something like that

- and if the car is misfiring you will get a warning on your DIC
Reply
Old May 9, 2007 | 11:51 AM
  #7  
Jistari's Avatar
Jistari
Safety Car
15 Year Member
 
Joined: Apr 2007
Posts: 3,640
Likes: 83
From: . New York
Default

Ok, check one problem off the list

I just noticed this yesterday, a very small roughness when ideling. Didn't remember it being there before. Drives/performs fine.

Didn't know this was common with the LS1.

Thanks
Reply
Old May 9, 2007 | 11:55 AM
  #8  
VinnyT's Avatar
VinnyT
Le Mans Master
15 Year Member
 
Joined: Jan 2007
Posts: 7,364
Likes: 6
From: Rocky Mount Virginia
Default

Rough idle is normal. My old 98 Z28 had the same thing.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-1

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
story-2

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
story-3

5 MOST and 5 LEAST Popular Corvette Model Years in History!

 Joe Kucinski
story-4

2027 Corvette Buyer's Guide: Everything You Need to Know!

 Joe Kucinski
story-5

10 Things C8 Corvette Owners Hate (But Won't Tell You)

 Joe Kucinski
story-6

10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

 Brett Foote
story-7

Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

 Joe Kucinski
story-8

Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!

 Michael S. Palmer
story-9

5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!

 Joe Kucinski
Old May 9, 2007 | 12:20 PM
  #9  
max'svette's Avatar
max'svette
Race Director
 
Joined: Mar 2007
Posts: 16,154
Likes: 0
From: Kali
St. Jude Donor '11
Default

These engines idle a bit rough... by that I mean you can feel the engine runing as opposed to most other modern cars. I asked the same question when I first joined. I chalked it up to "they all do that".

If your idle is jumping up and down and there are noises that are not supposed to be there you have other problems at hand.
Reply
Old May 9, 2007 | 12:34 PM
  #10  
RogerT's Avatar
RogerT
Pro
 
Joined: Jan 2007
Posts: 543
Likes: 1
Default Solution ?

I read in one of the well known C5 modification books about using spray throttle body cleaner periodicly to solve this very problem. I hope this helps.

Roger T
Reply
Old May 9, 2007 | 12:40 PM
  #11  
BobbyG's Avatar
BobbyG
Melting Slicks
 
Joined: Jul 2005
Posts: 2,572
Likes: 3
From: Rehoboth MA . . . NRA Life Member
St. Jude Donor '06-'07
Default

Did someone upgrade from the stock cam? Even a mild performance cam will change the idling characteristics of an engine.
Reply

Get notified of new replies

To Uneven idle





All times are GMT -4. The time now is 09:31 PM.

story-0
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-1
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-2
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE
story-3
5 MOST and 5 LEAST Popular Corvette Model Years in History!

Slideshow: 5 most and least popular Corvette model years.

By Joe Kucinski | 2026-04-08 13:25:01


VIEW MORE
story-4
2027 Corvette Buyer's Guide: Everything You Need to Know!

Slideshow: 2027 Corvette buyer's guide

By Joe Kucinski | 2026-04-17 16:41:08


VIEW MORE
story-5
10 Things C8 Corvette Owners Hate (But Won't Tell You)

Slideshow: 10 things C8 Corvette owners hate, but won't tell you.

By Joe Kucinski | 2026-04-01 18:36:07


VIEW MORE
story-6
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

Slideshow: Should you add one of these incredible Corvettes to your garage?

By Brett Foote | 2026-04-01 18:14:05


VIEW MORE
story-7
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

Slideshow: Every Corvette Grand Sport explained

By Joe Kucinski | 2026-03-26 07:13:44


VIEW MORE
story-8
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!

Slideshow: Breaking down the 2027 Grand Sport, Grand Sport X, Stingray, and LS6 V8.

By Michael S. Palmer | 2026-03-26 13:48:45


VIEW MORE
story-9
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!

Slideshow: 5 reasons bad drivers crash sports cars & 5 ways to avoid a costly shame!

By Joe Kucinski | 2026-03-25 16:32:55


VIEW MORE