*HELP*Misfire Codes Continue to Occur

[jdrop01]

I would replace the spark plug myself so I know it's been changed IMO.

[BubbaSS]

Originally Posted by tuki3388

it was a P0300 code, the notes from the dealership from my last visit state, replaced injector 3, removed intake, cleaned valves 3 times, could not duplicate after that point. But now the code is back roughly 2 months later.

Looked up code:

Possible causes

- Faulty spark plug (s)*
- Faulty ignition coil (s)*
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure

Alot of possible causes, but you can probably check for an intake air leak yourself. Also, you could possibly have a faulty sensor...Too many possibilities to really get to the bottom of it over the web, but this is a start.

[MrChrisLS3]

Try a different dealership. Maybe even a Cadillac dealership, they have experience with these engines. Point is some service dept are better than others.

A 300 code is misfire code, but how did they determine cyl 3? I had a coil pack go out on my old pre di caddy, and was a 303 code, meaning misfire cyl 3.

[spadz93]

Could be stupid, but if you have a code reader, swap the plug wires with a known functioning cylinder. Recheck codes. If the misfire moved to that cylinder, bad plug wire

[TooCool5]

Did you try this?
http://www.camaro5.com/forums/showth...light=chemtool

[Chevrolet Customer Svc]

Originally Posted by tuki3388

This is a question to anyone who can help me shed some light on this. I have a 2012 2ls Camaro. I' at roughly 44k miles and have a GM PP warranty still on the car.Cylinder 3 is misfiring, i've swapped coil packs from cylinder 3 - 6 and it still occurs. I've taken it to the dealership for years now and finally two months back they stated that carbon build up was the reason for my misfire codes in the cylinder. They replaced a coil pack and cleaned the carbon out per the GM techs orders. Back not even a year after I purchased the vehicle in 2013 cylinder 3 had misfire codes. The tech and the GM dealer replaced the coil pack on the cylinder in question and everything was fine for a time. Then the code came back randomly for a few years and if it did happen I could never get it to occur for the dealership. So I finally was fed up with it. Now its happening again after all of this and they charged me 335$ for the carbon cleaning stating that it was wear and tear. Which is understandable. Can anyone offer some advice? I'm in my last year of college and cant afford to keep dropping 300$ every two months to have them clean carbon deposits.

Hi tuki3388,

We're very sorry to hear that this concern continues after years of visiting the dealership, and we understand how frustrating and time consuming multiple trips can be. While we recognize that you’re seeking advice from other forum users before taking it back in, please know we’d be happy to help if you decide to do so.

Please feel free to private message us if you would like an additional layer of support.

Best,
Lauren E
Chevrolet Customer Care

[Flashpoint135]

My misfires ended up not being cured until they did a complete valve job under warranty. Really needed to clean the crap off the intake valves and the "top end clean" wasn't enough. Yes, it was ok for a couple months or whatever, but I was also getting cat failures / codes and they were replaced under warranty as well. Once the valve job was done, everything has been fine. To be clear, the dealership sent my heads out to a machine shop for steam cleaning, and the shop wouldn't steam clean without also doing a valve job, so my dealership / chevy covered all of it.

[tuki3388]

Originally Posted by TooCool5

Did you try this?
http://www.camaro5.com/forums/showth...light=chemtool

I have ran cleaner through my tanks and every winter I put seafoam or another cleaner additive in and this still occurs.

[tuki3388]

Originally Posted by MrChrisLS3

Try a different dealership. Maybe even a Cadillac dealership, they have experience with these engines. Point is some service dept are better than others.

A 300 code is misfire code, but how did they determine cyl 3? I had a coil pack go out on my old pre di caddy, and was a 303 code, meaning misfire cyl 3.

This technically will be my 3rd dealership with this issue. Im stuck 3 hours away from home and in a small town. My options are limited.

[tuki3388]

Originally Posted by Flashpoint135

My misfires ended up not being cured until they did a complete valve job under warranty. Really needed to clean the crap off the intake valves and the "top end clean" wasn't enough. Yes, it was ok for a couple months or whatever, but I was also getting cat failures / codes and they were replaced under warranty as well. Once the valve job was done, everything has been fine. To be clear, the dealership sent my heads out to a machine shop for steam cleaning, and the shop wouldn't steam clean without also doing a valve job, so my dealership / chevy covered all of it.

Last time I was at the dealership they told me they cleaned the valves heavily 3 times. Charged me an arm and a leg too. I've tried different gas, octance, gas stations, you name it.

[CamaroSS sleeper]

FIY P0300 is a random multiple cylinder misfire.

which means the ECU cannot determine which cylinder is misfiring or why.
otherwise it would state the cylinder number, i.e. P0301, P0302,P0303 etc..
the ecu has extremely good algorithms built in for failed coils, injectors, blown plugs among a million other variables...

what it cant determine is external variables.
an exhaust leak bad enough for the knock sensor to picking it up will cause this code.
or something is rattling at a very specific frequency triggering the random misfire.
i.e. only happens at a certain RPM or speed.
do you have headers?
check header bolt torque. 18ft/lbs if my memory serves me right.
check for worn engine mounts
anything loose that could be hitting the chassis or engine.

among other things to check that have already been discussed is
plugs
wires
coils
injectors.

but again the ecu is very good at recognizing any of the items above.

[tuki3388]

Originally Posted by CamaroSS sleeper

FIY P0300 is a random multiple cylinder misfire.

which means the ECU cannot determine which cylinder is misfiring or why.
otherwise it would state the cylinder number, i.e. P0301, P0302,P0303 etc..
the ecu has extremely good algorithms built in for failed coils, injectors, blown plugs among a million other variables...

what it cant determine is external variables.
an exhaust leak bad enough for the knock sensor to picking it up will cause this code.
or something is rattling at a very specific frequency triggering the random misfire.
i.e. only happens at a certain RPM or speed.
do you have headers?
check header bolt torque. 18ft/lbs if my memory serves me right.
check for worn engine mounts
anything loose that could be hitting the chassis or engine.

among other things to check that have already been discussed is
plugs
wires
coils
injectors.

but again the ecu is very good at recognizing any of the items above.

I appreciate the extra information. You are correct on the p0303 code, Im just going off of the last dealership that pulled the code, Im currently looking for the tech document I had them make a copy of. Back within like 10k miles of owning the car I had an evap code that kept coming back and coming back. Finally found out it was a pin hole size leak in the gas return line. So I couldn't agree more. Im just trying to figure out a solution to I don't get take at the dealership tomorrow, I already don't trust them.

[christianchevell]

As a fellow car enthusiast..Bummer, I would make it to a different shop and make sure they are using the real deal cleaning the carbon with a machine that injects chemicals at the right time and does the job for all the engine, and check and replace all that sides spark plugs checking their condition inspect all coil connections on that side and look for the condition of anything that could be showing buildup/wear. If you do not have a catch can investing in one may be a good idea. things that get old over time like O2 sensors and others can be a problem throwing codes that make you look elsewhere.

I too would check the headers bolts as aluminum expands and contracts a lot more than steel and bolts coming loose are a old problem form the advent of aluminum engines. Heck old chevy luvs that had aluminum engine heads would walk the bolts out of their little hemispherical heads until they were all just loose as heck..... and cleaning the valves at one place can be spraying carb cleaner down the throttle body......and at others they have invested thousands in to state of the art machines. I would worry about the condition of the affected cylinders but if the feeling is not there that its actually misfiring it could be a erratic short somewhere in a plug wire or coil wire connection. I would unclip and re-clip the coil wires check the grounds to the fuel injection especially. Good Luck!

[tuki3388]

Originally Posted by christianchevell

As a fellow car enthusiast..Bummer, I would make it to a different shop and make sure they are using the real deal cleaning the carbon with a machine that injects chemicals at the right time and does the job for all the engine, and check and replace all that sides spark plugs checking their condition inspect all coil connections on that side and look for the condition of anything that could be showing buildup/wear. If you do not have a catch can investing in one may be a good idea. things that get old over time like O2 sensors and others can be a problem throwing codes that make you look elsewhere.

I too would check the headers bolts as aluminum expands and contracts a lot more than steel and bolts coming loose are a old problem form the advent of aluminum engines. Heck old chevy luvs that had aluminum engine heads would walk the bolts out of their little hemispherical heads until they were all just loose as heck..... and cleaning the valves at one place can be spraying carb cleaner down the throttle body......and at others they have invested thousands in to state of the art machines. I would worry about the condition of the affected cylinders but if the feeling is not there that its actually misfiring it could be a erratic short somewhere in a plug wire or coil wire connection. I would unclip and re-clip the coil wires check the grounds to the fuel injection especially. Good Luck!

I appreciate it, this dealership is already on my S*** list for when they couldn't do a proper oil change and my baby was towed back in. All they did was give me a free oil change card, for 1 free oil change and they swore up and down there was no damage to the engine. I message the chevy customer guy who posted earlier. I love my car to death, I cleaned it daily before college and wouldn't trade it for the world. I am just tired of this run around.