Cold Start Misfire P050D

[mb1500]

2016 suburban out of warranty. P050D and P0300 codes stored. Randomly happens on cold starts on typically cold days. CEL lights up then goes off on its own. Has flashed repeatedly on other occasions, then again the light goes away. Misfire counter shows over 3,000 on cylinder 8 which is significantly more than any other cylinder.

Vehicle runs poorly when CEL flashes, otherwise runs fine. Light has stayed off for about a week now.

I’m guessing #8 needs a new injector, seems fuel related to me. Anyone have a similar problem?

 

[Stanlee83]

Greetings, I’m having the same problem. Did you get a fix for that problem?

 

[ReaperHWK]

I had this issue. It was a faulty fuel injector. I decided to replace all 4 on the same fuel rail though since I had to pull the intake and the fuel rail on the driver side. You need to replace all the orings on any injectors that get disconnected so I figure I’d just replace them if I’m in there. There is also a “s shape” fuel line under the intake that Chevy says needs to be replaced anytime the fuel rail is disconnected. The dealer should know about this part I picked it up there.

I actually replaced the fuel rail too it was so lodged in the engine block I actually bent the old one trying to get it out. Had to use a 4ft pry bar. They actually sell a special tool that is made to pull the injectors and fuel rails out of the injector bore. I guess this is a common issue.

 

[ReaperHWK]

2015 Tahoe, P050D Code (cold start rough idle)

Some history first. 1)Few weeks ago on a trip home the Tahoe threw a code, it was a P0300 Random Misfires. I could tell it was running rough. I replaced all the plugs(truck has about 120k miles) and it ran much better. P0300 went away. 2) A few days later it then threw a cylinder 8 misfire...

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