Car starts very rough when sitting 'cold'

[jtzako]

I'm wondering about something on my car. When I do a cold start after it has been sitting for a day or so it is very rough at first. And, since its in my garage and I dont want it dumping all the exhaust in there I back it out, and it acts like it wants to go too fast even at idle.

Is this a normal thing for this type of engine to do when its sitting cold?

[The Stig]

yes it's normal, the engine needs time to warm up first. And yes, these cars like to go fast.

[909Camaro!]

Yes its normal when its cold

[ECCamaro]

Mine kind of sputters at first.

[jtzako]

If its normal for this car thats fine.. it just seems rougher than it should be to me. Past cars never where anywhere near as cranky when they first wake up. )

[FLYBOY]

I know what you're talking about, mine does the same thing. And yes, it does sound a bit more rough than any other vehicle I've owned. I'm not too worried about it though.

[cab2g]

it might have a lot to do with the size of the engine and the loudness of the exhaust. A rough idle with a larger piston probably would cause more vibration. But I'm no expert. I love how rough my car sounds @ startup. Once the RPMs drop, it's harder to hear that beautiful idle unless I'm behind the car.

[1BADLS3]

Originally Posted by jtzako

I'm wondering about something on my car. When I do a cold start after it has been sitting for a day or so it is very rough at first. And, since its in my garage and I dont want it dumping all the exhaust in there I back it out, and it acts like it wants to go too fast even at idle.

Is this a normal thing for this type of engine to do when its sitting cold?

Yes. Totally normal, and it's because it's a high performance engine. For a stock, production engine it's got a mild cam which contributes to some of what you feel in terms of a rough idle.

All gas engines have some kind of fast idle when they're cold to keep them from dying. It's more noticeable on automatics because the high idle creates more pressure in the torque converter (kind of like you're pressing on the gas a little), so it surprises some people.

Also, add to the fact that it's a 426hp engine with over 400ft/lb of torque.

A Toyota Corolla at fast idle might be producing, for example, 15ft/lb of torque, so the additional pull might not be noticeable. But at the same idle speed, the LS3 might be putting out 35ft/lb of torque, so it feels like the car is trying to drive itself around.

[jtzako]

Yeah I do notice the excess torque when its like this. The cold brakes make it feel harder to keep it going slow as I pull out onto the driveway.

[v6]

Anyone have the engine block heater??

[jtzako]

I dont, but this issue isnt really about being all that cold. It can be 90 degrees in my garage and if my car sat for a day or two without being driven it will do this.

[SamHouseIII]

Mine does this too, thought it was a problem, little warm up and she was fine.

[Wakemaker89]

I haven't noticed this in mine but that may be because it's always been rougher than any other car I have owned so it seemed normal for the car.

[Parag]

block heaters are for old diesels because they wont start under 30 degrees. you guys hate this now try getting a race cam and a tune. dont even try to drive it until it warms. be glad it is not a carbed motor those are fun.