2011 LLT cyclinder missfire, need help

[nicko524]

So, I took my car into the dealership on Monday Dec 9th due to a check engine light that came up when I started my car early morning trying to go to work. It was on the cooler side for Los Angeles weather at 530 am probably around 45 degrees? Upon cold start up my car began to immediately idle rough, the whole car was shaking and the check engine light immediately came on. I turned it off and started it up couple more times and each time the idle seemed to slowly come back to normal but with a slight jump in rpms. I then proceeded to contact onstar with my car still running on idle and asked them to run a diagnostic. The onstar rep then said that I had a miss fire engine code and that theyre standard procedure is to take the car into the dealer to get it checked out (I figure this is a good idea because I have the extended warranty and the General Motors Protection plan as well). So I NEED to be at work in like 20 mins so I said I would call back later and I'll use another vehicle we have at home to go to work. I also wanted to see if they car would act up again on a cold start in the afternoon. So I go to work and get home around 1130 and start it up and a check engine light came up again and the idle was a lot better not quite normal, but still better. So I hit my little blue onstar button again and I talk to the rep and they say the same thing they told me early that morning so we make an appointment at the local dealer (Camino Real Chevrolet). I drop it off with them at about 1230 pm that same day. I told the Service guy exactly what happened and he told me he would take care of it for no problem and that he would keep me updated EOD each day. He didnt call me Tueday, but he called me Wednesday. He told me that we are going through all the systems and checking everything and that they also cleared the check engine light. He also told me that it's not acting up anymore so they don't know what is wrong so they want to keep it little longer and of course he apologized for keeping it so long. So Thursday goes by and he doesn't call and yesterday, Friday he calls and tells me my car is ready and that he is going to charge me $120 for a diagnostic and that they found carbon build up on the #5 cylinder that miss fired. They cleaned it with their "GM cleaner" and cleaned out all the systems and that it's running fine now. I asked him how my camaro (which has 38,600 miles on it) could have carbon build up so soon and how they could charge me that fee with my warranties I have. He told me it's probably whatever gas company I'm using that they charged me the diagnostic fee because it falls under maintenance. I told him I only use Shell, 76, and Chevron so how is that so then, what would cause carbon build up. Couldn't really give me an answer. So today (12/14) we went to the dealership to pick up my car with my father. He told me exactly what we told me on the phone yesterday and again we question how we would get charged diagnostic fees with the extended warranties we have if it's a fuel issue and we gas up at probably the 3 biggest gas companies in America (and we have proof with receipts since I got the car that I gas up there). He again tells me it wouldn't fall under my warranties and that it's simply a maintenance issue and that they really couldn't exactly tell me what was going on to get that carbon build up on the valve besides bad fuel. (sorry for the all the reading)

So my question to you guys here is what do you think could be wrong? was I wrongfully charged? and what can I do to prevent this from happening again?
I would appreciate any information through PM, email (nicko0524@gmail.com) or even txt (6262779210). Thanks in advance.

- Nick S.

[nicko524]

Cylinder* excuse my bad proof reading in advance

[Nutbutt]

Might want to start with a good catch can. There are a couple good ones out there I have a saikou Michi.
http://www.saikoumichi.com
Also look at the elite catch can.

[Eddiefuzz]

I hear Ya. That's one of the reasons I didn't buy the "Extended" warranty on my Camaro. They always find a different cause, that is not covered, of the engine problem. I bought my 20011 in November 2010 and I have had four of the six cylinder coil packs replaced in the first 15000 miles. One at a time and each time the dealer had my car for at least two days. It has the same symptoms as yours, rough Idle, little sputter, shout it off and turn it on and it might go away until next start up. So what I have done is bought a coil pack on EBAY, to have on hand, and if I get the rough idle, I take it to the local auto parts store. They will plug a diagnostic tool into my car and tell me the problem. BAM I fix it myself. ALSO, you need to get a Catch Can, The build up isn't coming from the fuel, it's coming from the oily air mixture that gets sucked into the intake manifold. Good luck with your car. I just hit 55000 today, running great since the catch can, and I Sea Foam it every oil change. MERRY CHRISTMAS!

[rtcat600man]

Carbon build up is normal on DI engines. Which is why so many of us have added the oil catch cans. There is no fuel passing over those valves, so no cleaning effect is taking place.

Do some research on the site for oil catch can and you will find plenty to read.

[nicko524]

Originally Posted by Nutbutt

Might want to start with a good catch can. There are a couple good ones out there I have a saikou Michi.
http://www.saikoumichi.com
Also look at the elite catch can.

Ill check it out! Thank you. Is this better than the RX catch can? I see everyone with those. I dont know alot about catch cans I have never used them before.

[nicko524]

Originally Posted by Eddiefuzz

I hear Ya. That's one of the reasons I didn't buy the "Extended" warranty on my Camaro. They always find a different cause, that is not covered, of the engine problem. I bought my 20011 in November 2010 and I have had four of the six cylinder coil packs replaced in the first 15000 miles. One at a time and each time the dealer had my car for at least two days. It has the same symptoms as yours, rough Idle, little sputter, shout it off and turn it on and it might go away until next start up. So what I have done is bought a coil pack on EBAY, to have on hand, and if I get the rough idle, I take it to the local auto parts store. They will plug a diagnostic tool into my car and tell me the problem. BAM I fix it myself. ALSO, you need to get a Catch Can, The build up isn't coming from the fuel, it's coming from the oily air mixture that gets sucked into the intake manifold. Good luck with your car. I just hit 55000 today, running great since the catch can, and I Sea Foam it every oil change. MERRY CHRISTMAS!

I will look into the coil pack as well. Thanks!

[nicko524]

Originally Posted by rtcat600man

Carbon build up is normal on DI engines. Which is why so many of us have added the oil catch cans. There is no fuel passing over those valves, so no cleaning effect is taking place.

Do some research on the site for oil catch can and you will find plenty to read.

I have been thinking about getting one just never thought it was going to need it this nor would it take this situation to make get one for sure. Guess I know what I am going yo buy myself for Christmas!

[Nutbutt]

Originally Posted by nicko524

Ill check it out! Thank you. Is this better than the RX catch can? I see everyone with those. I dont know alot about catch cans I have never used them before.

In my opinion it is the best. It has three stage cleaning and is fully customizable. For ease of emptying I have a ball valve option as well as a sight glass to see when to empty.
The elite is a good choice also. The screw off bottom make it real easy to empty. Just don't get one that is just an empty can from ebay.

[shrinkdoc]

Originally Posted by nicko524

So, I took my car into the dealership on Monday Dec 9th due to a check engine light that came up when I started my car early morning trying to go to work. It was on the cooler side for Los Angeles weather at 530 am probably around 45 degrees? Upon cold start up my car began to immediately idle rough, the whole car was shaking and the check engine light immediately came on. I turned it off and started it up couple more times and each time the idle seemed to slowly come back to normal but with a slight jump in rpms. I then proceeded to contact onstar with my car still running on idle and asked them to run a diagnostic. The onstar rep then said that I had a miss fire engine code and that theyre standard procedure is to take the car into the dealer to get it checked out (I figure this is a good idea because I have the extended warranty and the General Motors Protection plan as well). So I NEED to be at work in like 20 mins so I said I would call back later and I'll use another vehicle we have at home to go to work. I also wanted to see if they car would act up again on a cold start in the afternoon. So I go to work and get home around 1130 and start it up and a check engine light came up again and the idle was a lot better not quite normal, but still better. So I hit my little blue onstar button again and I talk to the rep and they say the same thing they told me early that morning so we make an appointment at the local dealer (Camino Real Chevrolet). I drop it off with them at about 1230 pm that same day. I told the Service guy exactly what happened and he told me he would take care of it for no problem and that he would keep me updated EOD each day. He didnt call me Tueday, but he called me Wednesday. He told me that we are going through all the systems and checking everything and that they also cleared the check engine light. He also told me that it's not acting up anymore so they don't know what is wrong so they want to keep it little longer and of course he apologized for keeping it so long. So Thursday goes by and he doesn't call and yesterday, Friday he calls and tells me my car is ready and that he is going to charge me $120 for a diagnostic and that they found carbon build up on the #5 cylinder that miss fired. They cleaned it with their "GM cleaner" and cleaned out all the systems and that it's running fine now. I asked him how my camaro (which has 38,600 miles on it) could have carbon build up so soon and how they could charge me that fee with my warranties I have. He told me it's probably whatever gas company I'm using that they charged me the diagnostic fee because it falls under maintenance. I told him I only use Shell, 76, and Chevron so how is that so then, what would cause carbon build up. Couldn't really give me an answer. So today (12/14) we went to the dealership to pick up my car with my father. He told me exactly what we told me on the phone yesterday and again we question how we would get charged diagnostic fees with the extended warranties we have if it's a fuel issue and we gas up at probably the 3 biggest gas companies in America (and we have proof with receipts since I got the car that I gas up there). He again tells me it wouldn't fall under my warranties and that it's simply a maintenance issue and that they really couldn't exactly tell me what was going on to get that carbon build up on the valve besides bad fuel. (sorry for the all the reading)

So my question to you guys here is what do you think could be wrong? was I wrongfully charged? and what can I do to prevent this from happening again?
I would appreciate any information through PM, email (nicko0524@gmail.com) or even txt (6262779210). Thanks in advance.

- Nick S.

Tell that SOB that you did not drop your car off for maintenance, you dropped it off because the engine malfunctioned with a code. Your warranty covers all expenses. Contact GM if he still insists on f'ing over you.

[shrinkdoc]

Originally Posted by Nutbutt

Might want to start with a good catch can. There are a couple good ones out there I have a saikou Michi.
http://www.saikoumichi.com
Also look at the elite catch can.

If this is to be expected then GM should be installing the catch cans. If they break then GM needs to honor the warranty. Anyone think all those Cadillac owners with the V6s are expected to go crawling around under there hoods installing catch cans? I don't think so.

[Nutbutt]

Nope, I see most Cadillac owners bring in their cars and having the upper induction cleaning every other year and paying for it, no questions asked.

[Ventmaster]

I believe Apex Speed is selling a nice catch can as well. The Rx cans are becoming hard to come by and I think there was some concern over the quality of their check valves on recently made batches.

But the bottom line is a catch can is a "must have" on the current generation of DI engines.

[Eddiefuzz]

Originally Posted by Nutbutt

Nope, I see most Cadillac owners bring in their cars and having the upper induction cleaning every other year and paying for it, no questions asked.

It's called a top end cleaning. My dealer said I was supposed to have it at about 25000 miles. That's when I researched and found out about Sea Foam. It's written up in DIY section here. The dealer wanted about $280, I use about 1/2 a can just before every oil change. I also take off the pelhem cover and wipe out the intake.