Rough Idle
Thread Starter
Heel & Toe
Joined: Nov 2025
Posts: 15
Likes: 7
From: Texas, America
Rough Idle
2019 GS with 12,000 miles
On startup the engine is smooth but once it settles down it has a rough idle. All other regimes are smooth and powerful and without complaint except when idling. When I test drove it I asked the previous owner about it and he said it was normal, which could mean it's just been that way for the 1.5 years he had it, or it is, in fact, normal. I'm new to the C7 and Corvette world so am still sorting out "normal". Other than that, I am truly enjoying this experience and wondering why I waited so long.
On startup the engine is smooth but once it settles down it has a rough idle. All other regimes are smooth and powerful and without complaint except when idling. When I test drove it I asked the previous owner about it and he said it was normal, which could mean it's just been that way for the 1.5 years he had it, or it is, in fact, normal. I'm new to the C7 and Corvette world so am still sorting out "normal". Other than that, I am truly enjoying this experience and wondering why I waited so long.
Instructor
Joined: Feb 2021
Posts: 162
Likes: 42
A video would help to determine whether it is really "rough" or not. If you can provide that, we can tell you if it is not running correctly. I can get you in contact with my tuner who is the head of calibrations at Late Model Racecraft (one of the best corvette shops in the world) to analyze and look at your tune and fix it for you. Or determine if you bought really hurt car - which is possible.
Safety Car
Joined: Jun 2003
Posts: 4,509
Likes: 239
From: Coconut Creek FL
I guess you need to quantify "rough". My Z51 Stingray starts up with a big boy bark (exhaust flaps open) and quiets down with some normal engine harmonics. It's not choppy, as if it has a big cam, but it's also not as smooth as a Cadillac either. You have a lot of engine under the hood, and perhaps it's just a matter of getting used to what she sounds like.
Drifting
Joined: Oct 2005
Posts: 1,349
Likes: 708
From: Terrell North Carolina
The C7 Corvette engine will have a slight :"Rough), as it will not be perfectly smooth, all is normal, I own (2) C7's and the idle has a slight bump in the idle, the engine has a moderate cam shaft to give you the all the endless power you will ever be able to use. As long as you have No :Checking Light" all is well with your Corvette.
Instructor
Joined: Mar 2014
Posts: 139
Likes: 45
From: Orange County, CA
After ~200 miles of ownership and rough idle starts, The P050D code triggered, "Cold Rough Idle". After a few seconds, the idle would smooth out as the engine warmed up. In the end, new injectors solved my issue. I assumed the code had been cleared before I took the vehicle. Not implying this is your case, but if the code pops up, you'll know.
Team Owner
Joined: Sep 2000
Posts: 24,992
Likes: 2,694
From: Far NW 'burbs of Chicago
St. Jude Donor '13
TX-
Can you find someone with a similar C7 to compare idle?
The Z06/ZR1 have a different engine. The base/GS cars have the same engine but the exhaust is somewhat different.
Can you find someone with a similar C7 to compare idle?
The Z06/ZR1 have a different engine. The base/GS cars have the same engine but the exhaust is somewhat different.
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Thread Starter
Heel & Toe
Joined: Nov 2025
Posts: 15
Likes: 7
From: Texas, America
How long have you owned the car and driven? I had a similar experience, purchased a pre-owned C7, relatively low mileage '17, with complete service history.
After ~200 miles of ownership and rough idle starts, The P050D code triggered, "Cold Rough Idle". After a few seconds, the idle would smooth out as the engine warmed up. In the end, new injectors solved my issue. I assumed the code had been cleared before I took the vehicle. Not implying this is your case, but if the code pops up, you'll know.
After ~200 miles of ownership and rough idle starts, The P050D code triggered, "Cold Rough Idle". After a few seconds, the idle would smooth out as the engine warmed up. In the end, new injectors solved my issue. I assumed the code had been cleared before I took the vehicle. Not implying this is your case, but if the code pops up, you'll know.
Thread Starter
Heel & Toe
Joined: Nov 2025
Posts: 15
Likes: 7
From: Texas, America