Runs rough at first morning start

[jrb3]

Anyone else have an issue with their car having a rough, uneven idle at the first start after the car has set? Mine always feels like it's going to die, like it's not getting enough fuel. No CEL and I run Quick Trip fuel, so it's Top Tier gas.

 

[zb50]

Anyone else have an issue with their car having a rough, uneven idle at the first start after the car has set? Mine always feels like it's going to die, like it's not getting enough fuel. No CEL and I run Quick Trip fuel, so it's Top Tier gas.

Mine idles rough too for a few minutes upon first startups, but it doesn't get to the point that it wants to die. If I take off without letting it settle after the first startup then it has inconsistent power for a few minutes.

 

[jrb3]

Mine idles rough too for a few minutes upon first startups, but it doesn't get to the point that it wants to die. If I take off without letting it settle after the first startup then it has inconsistent power for a few minutes.

What's weird is that mine has just started doing it in the last month. I have a turbo MR2 that you can't drive until it warms up for a while, but this is new to the Sonic. ZB50, you need to post a pic of the Model A!

 

[SONIC1.4]

My Sonic has been doing this since I first tuned it. Now with E85 tune it actually will die if I don't rev it a couple times. It's only for the 40 second warm up the car naturally has then it's back to normal idle

 

[Eric Smit]

it's because the BOV is wide open and venting during cold start.

 

[zb50]

What's weird is that mine has just started doing it in the last month. I have a turbo MR2 that you can't drive until it warms up for a while, but this is new to the Sonic. ZB50, you need to post a pic of the Model A!

I don't like sending threads off topic, but since this one has been answered and it is your thread, I will post a picture of the Model A.

This was very recent. It was the first time its been outside of the garage in about 4 years. Almost ready to fire.

 

[jrb3]

Wow, now THAT is a model A!!!

Anyway, my rough start feels like a misfire issue, but with no CEL, it's going to be hard to figure out. Or, it feels like a clogged fuel filter, but since the Sonic just has a sock and no external fuel filter, it can't be that!

 

[zb50]

Wow, now THAT is a model A!!!

Anyway, my rough start feels like a misfire issue, but with no CEL, it's going to be hard to figure out. Or, it feels like a clogged fuel filter, but since the Sonic just has a sock and no external fuel filter, it can't be that!

Thanks!

Mine also feels similar to what you are describing. According to what Eric is saying, it almost sounds like these cars run rich on cold start due to the venting of the BOV, which would cause the rough idle situations (kind of opposite to what you are thinking). Not sure if that is what is happening, but to me it sounds logical.

 

[Scot]

Anyone else have an issue with their car having a rough, uneven idle at the first start after the car has set? Mine always feels like it's going to die, like it's not getting enough fuel. No CEL and I run Quick Trip fuel, so it's Top Tier gas.

What are your coolant temperatures when you start it up. Sounds like you're using a fuel with a "high driveability" index that can make cold starts / idles a little lean. The fuel doesn't have as many "light ends" to help cold combustion - doesn't mean the fuel is bad at all - it is a common problem in the real world that causes all kinds of headaches for OEM calibrators.

 

[Chevrolet Customer Care]

Hi jrb3,

I’m sorry to hear of that your vehicle sometimes runs rough. I will like to contact your dealership on your behalf and discuss this further with them. Feel free to send us a private message with your full contact information, VIN, current mileage, and dealership name if our help is needed. We’re looking forward to hearing from you!

Kristen A.
Chevrolet Customer Care

 

[SuperFudd]

If your engine is un-modified, consider a leaky/cracked valve cover.

 

[ranvette]

Are these motors tuned ? no problem here idle is dead on no matter what out side temps are on cold start. And i am Vtuner tuned to the edge on 93 octane. If they are tuned have someone tune them that knows the engine management system well.

 

[Barnold]

I have I think the same problem. In the morning, or when the car sits for a few hours the car will run rough for 10-20 seconds. It can get bad enough that the traction light comes on. I see no issue after the 20 sec or so. MPG is the same, power, same. I had this problem at the 30,000ish mark, they replaced the head, now at the 70,000ish mark it is happening again. Going to the draler tomorrow I will keep you updated. The car is stock. Also had the tranny replaced at the 50k mark. Good thing this car has the 10/100

 

[Chevrolet Customer Care]

I have I think the same problem. In the morning, or when the car sits for a few hours the car will run rough for 10-20 seconds. It can get bad enough that the traction light comes on. I see no issue after the 20 sec or so. MPG is the same, power, same. I had this problem at the 30,000ish mark, they replaced the head, now at the 70,000ish mark it is happening again. Going to the draler tomorrow I will keep you updated. The car is stock. Also had the tranny replaced at the 50k mark. Good thing this car has the 10/100

Hey there!

How was your dealership visit last week? Has your concern been resolved? Please let us know if any further assistance is needed. We will be happy to help if we're needed!

Kristen A.
Chevrolet Customer Care

 

[Barnold]

The car is in the dealer, no news yet, pushing 10 days. I will give you a update tomorrow after I call the dealer

 

[SuperFudd]

Leaking coolant into a cylinder?
Do you get an exceptional puff of steam from the exhaust?

 

[Chevrolet Customer Care]

The car is in the dealer, no news yet, pushing 10 days. I will give you a update tomorrow after I call the dealer

Hey Barnold,

Let us know if you need any additional assistance with this! We would be happy to reach out to the dealership for further updates as well.

Patsy G
Chevrolet Customer Care

 

[Hemplacrosse4]

Glad I found this, my car is having the same issue. Has anyone found a fix for this? My car only has eleven thousand miles and I feel like it started doing it since the day I bought it. Is this just how the car runs in the beginning or is there actually something wrong with it?