LS3 - random missfire?
 

anybody have much experience with random missfire in the LS3?

at idle the tach dips every once in a while and i feel a shudder (very slight) and then sometimes at part throttle i seem to feel a "bump" form her.
I can hear it at idle standing outside the car too.
maybe i'm dreaming and am not used to the sound of the LS3...

no engine light but i'm not sure i want to take her back to the dealer so they can "play" with it...

please advise!
Thanks all!

If this is true

Funny how the 6.1 Hemi's for the 09 challengers had that same problem, but was fixed with a revised ECM some other's just used tuners

I think mine is doing something like that as well.

damn me 2, i dunno what it is but hopefully its not bad.

If im sitting in the car with radio off and just at idle.

It will kind of lope , somewhat of a shudder.

havent noticed while driving though

WOW guys let us know what that is when you find out. It can't be good for it.

Get those cars to the dealers so the problem can get called into GM, maybe the reflash that was supposed to be done at the dealer was not done or they need a new Tune. Either way the dealer has some LS3 experience, this is not a new engine for the tech's let them check it out.

how long should this take at a dealer?
i do NOT want to leave it overnight.

That is a question only the dealer can answer. Bring it in an stay with it and see, maybe an adjustment, may be just the way it is, may be they do not know.

Mine does the same thing...I thought it was just the LS3?

I also have a whine in my tranny from 1 - 2 - 3 gear. Anytime I shift after she warms the tranny whines. I'm going to the dealer either today or tomorrow to get the battery cable fixed and I'll ask them about both things then.

Wow
 

That whining :confused0068:sounds like a throw out bearing is bad !

NOBODY KNOWS!!!!

just got off the phone with the service manager of my local dealer. ( i bought somewhere else)
he told me not to worry about it until after 1K miles... said computers are set rich for break in.

????

I have the automatic, and the transmission also whines in 1st and 2nd, I don't know about 3rd, by then it usually smoothes out and sounds like a normal V8. The car will sometimes have a bump at idle, and it made me think that someone rear ended me. Also at idle it's not very smooth at all, maybe i'm just used to a smooth running GMC truck.

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