Misfire at Idle on #3 and #5 P0300

[GILIAS]

Hello Folks, I need some advice. So my 2017 Sierra 6.2 started to shake at idle just a bit, not to bad but noticeable. I took it to my mechanic and did a live scan. He noticed that #3 and #5 were misfiring but only at idle. When i gave it gas no misfires were detected. He also told me that my truck has a special warranty for the fuel system so i took it to the dealership. They swapped out the injectors on #3 and #5 and said if that didn't help then more than likely i had a bad lifter. The lifters are not covered as i have 83000 miles. So what do i do at this point? Engine runs great and i don't hear an noise coming from the engine.  Please advise.

[durandetto]

You didn't mention if the injectors fixed the issue or not. I had the same issue on mine and replaced all the injectors on that bank and the problem hasn't come back. It's not it common for the lifters on 3 and 5 to fail as they are not it afm lifters.

If the problem is still there I would start by swapping plugs then coils to see if the problem follows the plug or coil. If so replace said part. If not you'll need someone to dig in deeper and see if it's a mechanical failure.

Sent from my SM-G998U using Tapatalk

[Skeeterhawk]

Ok guys I have the same problem on my 2017 Silverado 5.3 litre.

Throwing codes P0303,P0300,P050D.

 

Dealership said 3 bad injectors. True??? Covered under warranty?

  My truck has 28500 miles and 4 years old. No extended warranty.

 

 

[Doublebase]

13 hours ago, Skeeterhawk said:

Ok guys I have the same problem on my 2017 Silverado 5.3 litre.

Throwing codes P0303,P0300,P050D.

 

Dealership said 3 bad injectors. True??? Covered under warranty?

  My truck has 28500 miles and 4 years old. No extended warranty.

 

 

I don't believe they're covered...GM doesn't consider injectors part of the power train warranty (they consider them electrical).

[Skeeterhawk]

3 hours ago, Doublebase said:

I don't believe they're covered...GM doesn't consider injectors part of the power train warranty (they consider them electrical).

So why do folks in California get free injector replacement for up to 150K or 10 years?

[Doublebase]

1 hour ago, Skeeterhawk said:

So why do folks in California get free injector replacement for up to 150K or 10 years?

Two simple reasons...

 

GM likes people that live in California better or people in California do not get fuel injectors covered under power train warranty.

[Skeeterhawk01]

All injectors replaced. Problem still there. They replace all lifters on left bank. Problem is gone.

Drive the truck 2K miles over the course of 5 months. Check engine light comes on and throws P0303 code. They say bad fuel injector on number 3 cylinder. Will get truck back tomorrow. Oh when they decided to replace all the lifter on left hand, they did say lifter on cylinder #3 was bad. Why didn't they replace the camshaft too?

So is the problem still there? Just have to wait and see if #3 fails again.

[Skeeterhawk01]

All injectors replaced. Problem still there. They replace all lifters on left bank. Problem is gone.

Drive the truck 2K miles over the course of 5 months. Check engine light comes on and throws P0303 code. They say bad fuel injector on number 3 cylinder. Will get truck back tomorrow. Oh when they decided to replace all the lifters on left hand, they did say lifter on cylinder #3 was bad. Intake or exhaust, didn't say.Why didn't they replace the camshaft too?

So is the problem still there? Just have to wait and see if #3 fails again.

This is Skeeterhawk by the way.Forgot my sign on stuff so signed in with google instead.

Edited November 4, 2021 by Ron McMaster

[Skeeterhawk01]

Yes injectors are covered if you scream loud enough. If you live in Cali or not.