[JamesNoBrakes]

Unless they tell me the car is ready tomorrow, I'm mailing them the certified-mail lemon law letter after work.

[oneredry]

mine started happening after I installed my 1 step colder plugs. this is normal and as you mentioned it does go away after it starts to warm up. Do you have one colder plugs?

[JamesNoBrakes]

Originally Posted by oneredry

this is normal

No, it is not normal for the car to jerk around (backwards) while the engine cuts out during the first few miles due to misfire. I had an LS3 before this and I know what I'm talking about.

[oneredry]

Originally Posted by JamesNoBrakes

No, it is not normal for the car to jerk around (backwards) while the engine cuts out during the first few miles due to misfire. I had an LS3 before this and I know what I'm talking about.

I'm talking about after installing the colder plugs.... normal plugs? no. plugs that are colder on a cold start up? yes. (or I should say has a tendency to sputter a bit till warmed up)

[vtirocz]

Originally Posted by JamesNoBrakes

No, it is not normal for the car to jerk around (backwards) while the engine cuts out during the first few miles due to misfire. I had an LS3 before this and I know what I'm talking about.

Is your car behaving differently than other '16-'19 Camaro SS cars the dealer has on the lot?

[JamesNoBrakes]

Originally Posted by vtirocz

Is your car behaving differently than other '16-'19 Camaro SS cars the dealer has on the lot?

Yes, it misfires when the engine is cold. I thought we had already covered that.

[sadpanda]

It sounds like you have your mind made up... I doubt they will lemon but they may offer a buy back. At which point you are going to go out and buy what? A Challenger?

[Krowser]

Originally Posted by KLR ZL1

Humm this is interesting. I have noticed on cold starts that as the idle starts to drop to 1000 rpm the motor has a rough idle then stops. Not sure if this is the same thing , but it sure sounds like it. I believe it to be the DI injectors. I have blipped the throttle when it does it and it stops. I have also held the throttle at about 1200 rpm and it seems to not be as rough. I hate bringing my vehicles to the dealers because they are incompetent and or damage my vehicles. And that has happened more than I care to say and is a whole new issue to deal with. So I hope it isn't too serious and someone can chime in to give us a remedy.

There may be a faulty injector...have them checked at your dealership..

[EMTNLSS]

Originally Posted by KLR ZL1

Humm this is interesting. I have noticed on cold starts that as the idle starts to drop to 1000 rpm the motor has a rough idle then stops. Not sure if this is the same thing , but it sure sounds like it. I believe it to be the DI injectors. I have blipped the throttle when it does it and it stops. I have also held the throttle at about 1200 rpm and it seems to not be as rough. I hate bringing my vehicles to the dealers because they are incompetent and or damage my vehicles. And that has happened more than I care to say and is a whole new issue to deal with. So I hope it isn't too serious and someone can chime in to give us a remedy.

Yep this is the exact same thing that is happening to mine. Blipping the throttle or holding does the same thing as you describe also. I log it when it's doing the cold start and have a lot of misfires but as soon as the RPM's drop and level out I get none and have no issues driving. It also sometimes triggers the CEL and sometimes nothing pops up. I plan on switching the coils around to see if that fixes it but i'm also thinking it's probably the injectors. It's just really cold and snowy here so when it warms up to a decent temp i'll start switching stuff around.

[wjones14]

Originally Posted by JamesNoBrakes

Unless they tell me the car is ready tomorrow, I'm mailing them the certified-mail lemon law letter after work.

Did you follow through with this?

I feel really badly for your experience with the car. I leaned on you for your opinions while shopping for a Camaro, through the forums here and PMs, and learned a lot. I know how much you were looking forward to the car, and how pleased you were when you finally got it.

I can't even imagine how you're feeling now. Is your faith in GM/Chevrolet completely destroyed, or do you still hold hope that the manufacturer or dealer will somehow come through and resolve this to your satisfaction?

I'm still trying to figure out if this is a widespread problem or somewhat rare? Do you have any indication other than the few members of this forum who claim to have the same or similar issue?

Not sure what else to say other than best of luck.

[JamesNoBrakes]

Originally Posted by wjones14

Did you follow through with this?

I feel really badly for your experience with the car. I leaned on you for your opinions while shopping for a Camaro, through the forums here and PMs, and learned a lot. I know how much you were looking forward to the car, and how pleased you were when you finally got it.

I can't even imagine how you're feeling now. Is your faith in GM/Chevrolet completely destroyed, or do you still hold hope that the manufacturer or dealer will somehow come through and resolve this to your satisfaction?

I'm still trying to figure out if this is a widespread problem or somewhat rare? Do you have any indication other than the few members of this forum who claim to have the same or similar issue?

Not sure what else to say other than best of luck.

I did mail the letter to them, I got the return receipt today. Based on my on-star messages, the car is back in the shop getting worked on. Neither the shop or the senior service advisory with customer service has called me this week. The thing is, I really like the car, it worked just fine during most of the summer. It's likely an injector or coils, but the dealer seems too incompetent to figure that out. I'm not going to pay for all the extra stuff they've done that they said was the problem, when it was obviously not. That may mean legal action still, but under the lemon law, they have 30 days to make a final attempt at repair, and if they do, I'll be fine. This is the same company that owns the BMW dealership, where an attendant brought my car around after service and rammed it into a curb, messing up the bottom of the bumper/fascia and requiring them to get it fixed. Unfortunately, up here, it's kind of a captive audience so there isn't much competition. Usually the threat of any kind of legal action most businesses will do the right thing pretty quickly.

Example of the letter, excluding the backup documents and statements:

I am stating that:
(1) The vehicle has a nonconformity;
(2) I have provided a reasonable description of the nonconformity;
(3) Xxxxx has made a reasonable number of attempts to return the vehicle to conformity within a reasonable amount of time, and;
4) I demand a refund or replacement vehicle to be delivered on the 60th day after the mailing of this written notice.

This is based on the verbiage of our state's lemon laws. The letter goes into much more detail, but as of today, they have it, they have 10 business days to respond to my letter. We'll see.

Based on the description in this and other threads, it does sound like a few people have or had the exact same issue. I had a gen 5 with an LS3 so I have a pretty good idea what a normally-operating engine is like.

[JamesNoBrakes]

Looks like it has turned out for the best, supposed to pick the car up tomorrow.

[EMTNLSS]

Originally Posted by JamesNoBrakes

Looks like it has turned out for the best, supposed to pick the car up tomorrow.

Awesome! If it is fixed let us know what the dealer did.

[Elite Engineering]

Depending on the miles on the engine, it could be the initial signs of the intake valve coking. What make/model of catchcan did you have installed and was it on since new? Here is what occurs and why it is only at cold start to begin with. As the deposits begin to build, it is never an equal amount on each cylinders valves, those closest to the point of ingestion will build quicker and more severe while those furthest will build it less severe. As the upstream O2 sensors read each bank as an aggregate, or all 4 cylinders on a side, all injectors will deliver equal amounts of fuel, so each cylinder will be actually a bit richer or leaner depending on the level of deposits.


Below is a valve as it looks like when new:





Note the shape, the graduated radius, the undercut stem, and the satin swirl finish on the valves back sides. This is where the deposits build. ANY variance from the shape and texture will have a negative effect on the incoming air flow, or air charge. While to most, this is gradual and wont be noticed until misfires and hesitation off idle is evident, and the amount of variation is slight in the beginning, by 20-30k miles most have become severe enough (and yes I know, some say "That dose not look too bad"...) ANY deposits have an effect, and the worse the deposit, the worse the build up, the worse the effect. If these design attributes I mentioned above did not make a difference, GM nor any other engine designer would certainly not spend millions to go through all of the flow testing and effort to make them as precise as they do. they would just be a plain finish and shape, not the complex designs they do.


So, you will have some cylinders running richer than intended, and some leaner. While the degradation is gradual, so not noticed until severe, it is real. And some say "Ill clean them every 20-30k miles....but that does not prevent the wear to the valve guides. Look closely at these pictures:





(above is a valve at 32k miles, not severe but enough to cause cold start misfires. And the colder the heat range of the plugs, the more evident the cold start misfire will be). Note how the build up on the stem gets scraped down? This is from the valve cycling up and down in the soft brass guides. This is causing wear with even a slight amount of build up. The worse the build up and the more crystallized the deposits from high heat baking it with no fuel contact to cool them, the more wear occurs to the guides. This is something we have not had to deal with since the carburetor went away and port fuel injection kept the valves cool, clean, and free of any deposits as this 142,000 mile LS engines valves show:









You will never see the severity as shown below like earlier GDI engines experienced as GM and all others have made some great progress in slowing the rate and severity of the coking deposits, but it cannot be eliminated. Even using our best solution, the E2-X system which traps 95% of the "gunk" causing this, that will only prevent app. 85% of the deposits. Far better than no can or one of the common designs that allow 50-60-70% to pass through and still be ingested, the back filling of the port with burnt gasses to emulate the EGR valves function for emissions will always result in some deposits.


Why don't you want to use a Seafoam or other solvent based engine running cleaning? While they are safe for old port injection and carbureted engines where soft carbon would coat the piston tops and combustion chambers, these deposits bake into a hard crystalline form that when loosened and shed (and the most any of those will clean is 20-40% of the deposits) while most is expelled out the exhaust, some is forced between the pistons and cylinder walls and that is when damage occurs such as this picture shows on the piston skirts:






And one of the more severe risks associated with an engine running cleaning is if a large enough chuck is loosened and it gets stuck as the picture below shows, the piston will hit that valve and bend it as happened below:






So, this is something all GDI owners have to deal with.



Will your engine just "blow up" as some of the anti air/oil separation people claim we say if you don't take steps? Of course not. We have NEVER made those claims. And this is why we go into such technical detail when we share this information. And yes, some of you have read this before and don't care, that's fine as well, but there are always new members that DON'T know this so this is why we step in and share this in threads with related subject matter.


You WILL get longer life out of your engine guaranteed. You will lose far less power over time by installing a proper system (and yes, we have read the long term driving reports that claim no power loss, we have yet to see a single one with 20k or more miles that did not regain lost power as the example below at 20k miles. He regained nearly 20 whp. And we challenge anyone to do the same...actually do a before dyno, then a manual cleaning and after dyno the same day on the same dyno and see for yourself. Validate and verify what we share here:






And when you study the graph above, you can see the higher the RPM's where the disruption in air charge becomes more pronounced from the deposits, the greater the power loss was.


We do not know for sure this is the cause of your cold start misfires, but it is a common early symptom that a manual cleaning will correct. Try it and see if we were correct or not. Don't guess, actually look at your own valves. Takes minimum tools and 10-15 minutes to carefully remove your intake manifold so you can see them up close and personal. You don't "take apart your whole engine". Try it and share what you find.