Slightly rough idle ... Normal?
Thread Starter
Race Director
Joined: Apr 2001
Posts: 19,329
Likes: 15
From: Saint Augustine, FL
Mid-TN Events Coordinator
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16
Slightly rough idle ... Normal?
I'm not even 100% I have a problem, but when my car is idling, it's a little rough. It's not bad by any means, and I have always seemed to have had it since I bought it (with 17K miles). The only reason I brought it up is the other day when scanning at cold idle (open loop) the car is pretty darn smooth. The moment it goes into closed loop it gets rough. The O2 sensors look to be both working, the plugs and plug wires are new, I use good gas, etc.
I really am just looking for a "this is normal" reply. I really want to make sure everything is 100% before I get my headers and LS6 intake put on.
Thoughts?
I really am just looking for a "this is normal" reply. I really want to make sure everything is 100% before I get my headers and LS6 intake put on.
Thoughts?
Melting Slicks
Joined: Nov 2003
Posts: 2,898
Likes: 5
From: Plainfield, IL
Try this if you can reach the 02 plugs. Totally disconnect your front 02 sensors and drive around for a bit. When I had my old 97 Z28 I noticed the car run MUCH smoother in open loop all the time and like you said as soon as closed loop kicked on and it read from the 02's the idle became more rough. You will get a engine light on but that doesnt matter.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Intermediate
Joined: Oct 2005
Posts: 47
Likes: 0
I noticed that too! Woo Hoo!!
As a former hot rod drag racer and builder, I can tell you that it is what used to be known as "lope". It comes from the cam lobes having a wide overlap. The more overlap, the worse it is. Also, the worse it is, usually the more powerful the car is. This allows for more efficient VE at high RPMs. The LS1 was designed to make it's power upstairs, so a lopey cam makes sense.
I love it!
As a former hot rod drag racer and builder, I can tell you that it is what used to be known as "lope". It comes from the cam lobes having a wide overlap. The more overlap, the worse it is. Also, the worse it is, usually the more powerful the car is. This allows for more efficient VE at high RPMs. The LS1 was designed to make it's power upstairs, so a lopey cam makes sense.
I love it!
