Rough Idle

[wyoming zl1]

When i was at the dealership about 2 months ago the manager gave me his avalanche demo to drive around while i was having service done. it was a special model with a 6.2 liter super charged engine in it, i think he called it a Badalanche or something. I noticed driving it that at low idle the whole car kinda shook and if you turned the wheels at low idle it almost acted as if it might kill the engine. But when you hit the throttle....Holy crap that thing was scary!!!

[SC2150]

Until the rings seat you are also getting alot of oil ingestion into the intake air charge.....pull the TB off and look inside with a flashlight to see what I mean. Will cause some misfire at times.

[mechanic1]

Originally Posted by bcguy

My 2ss does this and there is a big difference between cam lope and a rough idle that my car has. It's not all the time but sometimes it just runs like its missing. Anyone else have any insite on this

My 2ss did this right from the start..........sitting in the car sometimes feels like there is a slight miss..........but not always, rather inconsistent..........took it right away to the dealer and had them throw it on the engine analyzer.........absolutely no problems showed up..........perfectly normal..........go figure.........on the ss forums some guys said it was bad gas...........who knows

[Blue Menace]

Originally Posted by SC2150

Until the rings seat you are also getting alot of oil ingestion into the intake air charge.....pull the TB off and look inside with a flashlight to see what I mean. Will cause some misfire at times.

So the problem goes away on its own or do you need to clean the TB?

[OldScoolCamaro]

No disrespect but you may not be used to the idle of a high performance motor, they do shake a bit at idle, even factory ones....yes, the cam has a 'bit of overlap, some rumble, it's purfectly normal for a performance motor.....and FYI this is tame compared to a worked motors idle. Shake, rattle, and roll....

[SC2150]

Originally Posted by Blue Menace

So the problem goes away on its own or do you need to clean the TB?

When the rings seat properly it will not be as bad, but w/out a good functioning catchcan you will always have oil ingestion.

Pull the TB and take a look and see. If you need more details search for "understanding the need for a oil separating catchcan"

[actireman]

Originally Posted by OldScoolCamaro

No disrespect but you may not be used to the idle of a high performance motor, they do shake a bit at idle, even factory ones....yes, the cam has a 'bit of overlap, some rumble, it's purfectly normal for a performance motor.....and FYI this is tame compared to a worked motors idle. Shake, rattle, and roll....

No disrespect back, but I don't think you are reading what they are saying. It only does it every now and then. Mine was doing it yesterday, and it was bad enough it got my attention and made me look at the tach to see if it was below 500 RPM's. I've had a lot of race engines and they do shake at idle----EVERYTIME AND ALWAYS, they don't come and go like this does.

[paul2010]

I would guess that it is a result of the computer adjusting the air fuel ratio. When the engine is cold it may restrict the airflow and alter the pressure for better performance.

[SC2150]

These motors will idle very smooth if all is working correctly...ZL1 included. Even with aftermarket cam if the LSA is large enough a smooth idle is possible.

[BluegraSS]

In stock tune my L99's idle is a little lumpy. It's much smoother with a proper tune.

Oops, I didn't realize this was a ZL1 thread.

[LINMUP]

My 07 GMC 6.0L does it every now and then....and it's not a performance vehicle...I think it's the nature of the beast with LS engines....I kinda like it, feels likes it's got a bit of a cam lol.