Cylinder #6 misfire

Codyderby1 · August 18, 2019

My 14 Silverado is throwing a cylinder 6 misfire code. This is now the 3 time with in a 1.5 month span it has been into the dealership to be repaired. They have replace all of the lifters and the cam, 4 fuel injectors and i replaced all if the plugs in it two days before it went to the dealer the first time and when you start it up after it has been sitting for a peroid of time it throws white smoke every where like it did when it smoked the cam. Everything has been covered under my warranty thankfully but even the dealer seemes to be stumped now. They have been communicating and running test with gm for the past week. Any ideas?

Thanks in Advance

1SLOW1500 · August 18, 2019

So misfire and smoke? I would lock out dod and data log a scan. But any reason the harness wasn't metered out and the coil packs switched or replaced?

I would do a cylinder compression test. And find out about the smoke. Sounds like oil. But after those quick checks I would just get a over ride code and get a new engine installed.

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Codyderby1 · August 18, 2019

I dont know if it is due to the dod since i installed my lift and new tires the truck doesn't activate the 4cyl mode any more unless im doing like 30 or below. I would love a new motor but everything is going through my extended warranty which only has 11,000 left on it

1SLOW1500 · August 18, 2019

Maybe someone has a better idea. Something in my head is saying damaged valve or valve seat. Would cause a combustion issue I would if the knock sensor is picking anything up? White smoke is oil but where and how?

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Codyderby1 · August 18, 2019

When they replaced the lifters and cam it had a knock but nothing since then

1SLOW1500 · August 18, 2019

I have said this before but I will recommend it again. Just because you have the extended warranty don't be afraid to get a second opinion.
In my mind there is damage somewhere internal.
If they can scope it on get it in compression test inwould push for new motor but for peace of mind and time.

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silveradosid · August 18, 2019

blue smoke is oil, white smoke is coolant

1SLOW1500 · August 18, 2019

Oh yes you are correct. Been a long day. Ok then coolant. I would pull a plug and and scope it then possibly pull the intake and inspect. Not that the misfire isn't important but one issue at a time and the smoke is a bigger issue.

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Bash74 · August 18, 2019

Even though its just throwing a #6 misfire it might be the head.

#PIP5498:
P050D P0300 Setting On A Cold Start

A vehicle may have a problem of DTC P050D setting along with a P0300 after a cold start up.
White smoke and/or coolant odor may come from exhaust for an extended period of time at cold start as well.

Misfires on start up only, with high rates always on one cylinder, can be suspect for coolant entry at the liner to deck face casting or the casting line in the intake port of the cylinder head.

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Jfuller · August 18, 2019

I've had a 2019 Silverado 1500 6.2 for 4 days and am getting a rough idle cold start and p050d code. 226miles. How can that be possible.

Bash74 · August 19, 2019

I've had a 2019 Silverado 1500 6.2 for 4 days and am getting a rough idle cold start and p050d code. 226miles. How can that be possible.

Something as basic as bad gas can cause it. Could also be a bad injector or just bad connection to injector. If you can check and see misfire count.

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1SLOW1500 · August 19, 2019

Sorry but I don't understand how the dealership can't figure this stuff out. Well that isn't completely true. I do they do care.and have never been equipped to do so they have enough knowledge to turn wrenches and swap parts.
True master mechanics start a shop and have to deal with everything and get it right the first time or it is out of their pocket.
With my device I can shut off injectors and check the bank or pulse width. Then by removing them I can flow test them with a a machine that cost 2 time my truck. Or for 60 buck replace them. So you know what they do. And that is fine but as you see it is like buying a lotto ticket great if it works if not how many parts you going to replace to get to the issue? That is why I said swap the engine.

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Bash74 · August 20, 2019

Sorry but I don't understand how the dealership can't figure this stuff out. Well that isn't completely true. I do they do care.and have never been equipped to do so they have enough knowledge to turn wrenches and swap parts.
True master mechanics start a shop and have to deal with everything and get it right the first time or it is out of their pocket.
With my device I can shut off injectors and check the bank or pulse width. Then by removing them I can flow test them with a a machine that cost 2 time my truck. Or for 60 buck replace them. So you know what they do. And that is fine but as you see it is like buying a lotto ticket great if it works if not how many parts you going to replace to get to the issue? That is why I said swap the engine.

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His delearship is lazy. Troubleshooting procedures have been put out on exactly how to figure his issue out so I don't see why they haven't. I wonder if the dealer has even checked the head which GM has put out exactly how to do.

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Sean Floyd · December 1, 2023

2019 Chevy Silverado 5.3 l. A number 6 missed fire coad reads po208 open how to fix

C.Kerley · March 14

I have a 14 Silverado 5.3 with #6 cyl misfire. I did have a collapse lifter but with that being said. I also had a compression check, injector replaced, HP fuel pump replace while there, and still a misfire. Plugs and coil have been swapped. Only thing I can think of is a cam. Any thoughts to add?