C5 Tech Corvette Tech/Performance: LS1 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace
Sponsored by:
Sponsored by:

Random high idles

Thread Tools
 
Search this Thread
 
Old May 15, 2020 | 10:42 AM
  #1  
Chris86581's Avatar
Chris86581
Thread Starter
Advanced
Conversation Starter
All Eyes On Me
Liked
Loved
 
Joined: May 2016
Posts: 74
Likes: 2
Default Random high idles

Morning everyone, i have a 2004 z06 that has random high idles. when i start the car sometimes it jumps to about 1800 RPM then stays there 10 sec before going down to idle. when coming to stops or red lights sometimes it stays at 1800 ish for about 15-20 sec before coming down to idle, could this be a vacuum issue??? car has a LS3 swap and cam with the LS2 silver blade TB and has been tuned recently.
Reply
Old May 15, 2020 | 11:13 AM
  #2  
helga203's Avatar
helga203
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2010
Posts: 5,987
Likes: 719
Default

Originally Posted by Chris86581
Morning everyone, i have a 2004 z06 that has random high idles. when i start the car sometimes it jumps to about 1800 RPM then stays there 10 sec before going down to idle. when coming to stops or red lights sometimes it stays at 1800 ish for about 15-20 sec before coming down to idle, could this be a vacuum issue??? car has a LS3 swap and cam with the LS2 silver blade TB and has been tuned recently.
I would put my money on vacuum leak. Dont really know anything out of the blue can cause that. Get starter fluid and start spraying manifold all hoses to brake mc the big hose. See what happens.
Reply
Old May 15, 2020 | 11:53 AM
  #3  
Chris86581's Avatar
Chris86581
Thread Starter
Advanced
Conversation Starter
All Eyes On Me
Liked
Loved
 
Joined: May 2016
Posts: 74
Likes: 2
Default

Is it safe to do that with starter fluid?
Reply
Old May 15, 2020 | 12:07 PM
  #4  
C5 Diag's Avatar
C5 Diag
Moderator, Tech Contributor
Supporting Lifetime Gold
10 Year Member
Veteran: Air Force
Liked
Community Favorite
 
Joined: Sep 2013
Posts: 15,435
Likes: 3,981
From: Cape Coral, Florida
Default

I'd take the car back to your tuner !!
Reply
Old May 15, 2020 | 12:11 PM
  #5  
runner140*'s Avatar
runner140*
Le Mans Master
20 Year Member
Veteran: Army
Liked
Community Favorite
 
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Default

Originally Posted by Chris86581
Is it safe to do that with starter fluid?
Or use a small tank of propane with a long rubber hose.
Reply
Old May 15, 2020 | 02:52 PM
  #6  
feeder82's Avatar
feeder82
Safety Car
20 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Mar 2005
Posts: 3,742
Likes: 1,205
From: Wisconsin
Default

I'll second the tune as a issue, idle quality is tricky to tune.
Reply
Old May 15, 2020 | 06:14 PM
  #7  
helga203's Avatar
helga203
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2010
Posts: 5,987
Likes: 719
Default

Originally Posted by Chris86581
Is it safe to do that with starter fluid?
Yes do it all the time. Just came from outside tracking a high idle and we found it with starter fluid, but if your not comfortable dont do it. Yes back to tuner like they said. I bet they will say its not there tune. Been there done that but you might have some good guys. After i had mine tune ran similar to yours brought it back they took it for 30 mins and said it was fine we made adjustment. started it up and all they did was turn the idle up to 1k rpm then they tried to charge me 200 more. They will never forget me after i spoke my mine.

Last edited by helga203; May 15, 2020 at 06:19 PM.
Reply
Old May 15, 2020 | 06:23 PM
  #8  
Chris86581's Avatar
Chris86581
Thread Starter
Advanced
Conversation Starter
All Eyes On Me
Liked
Loved
 
Joined: May 2016
Posts: 74
Likes: 2
Default

@demon666 yeah had some TB issues before so idle sucked, after new cam/TB i took it back twice cause idle was odd. theres not many tuners near me unfortunately.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-1

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-2

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-3

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-4

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-5

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-6

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-7

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

 Michael S. Palmer
story-8

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

 Joe Kucinski
story-9

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
Old Jun 15, 2020 | 12:09 PM
  #9  
Chris86581's Avatar
Chris86581
Thread Starter
Advanced
Conversation Starter
All Eyes On Me
Liked
Loved
 
Joined: May 2016
Posts: 74
Likes: 2
Default

*update* turns out the tuning was REALLY bad, went to a different tuner and he fixed it!
Reply

Get notified of new replies

To Random high idles





All times are GMT -4. The time now is 07:48 AM.

story-0
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-1
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-2
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-3
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-4
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-5
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-6
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-7
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-8
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-9
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