Jump to content

Engine Missfire

Buzz1

By Buzz1
in Troubleshooting & Recalls

 Share

Recommended Posts

Buzz1 Enthusiast

Buzz1

Posted
Posted (edited)

Hello,

 

I have a 2016 Silverado LTZ (8 Speed, 5.3) with around 110,500 miles currently.  Earlier, back in December (107,339 Miles) after the truck had sat for a couple of days, I was driving down the flat highway (Going around 72) and all the sudden I noticed a flashing check engine light. I pulled over and then the light turned steady. I called onstar and they informed me that it was a engine missfire, since the light was no longer flashing I continued to drive. Later the light turned itself off. Later on in the trip the check engine light started to flash and then turned solid. Again, I called Onstar and they told me it was a misfire. The light hen turned off the next day.  I also took a trip to auto zone after the light had turned off and got them to scan my truck and they gave me a more detailed answer. There was a pending code of P0305 for a misfire in cylinder 5.  The weather during that drive was clear but very cold, around freezing. The engine never fully warmed up. I thought it was just a random issue, or bad fuel until this evening. I was driving going around 40 miles per hour, (Engine fully warmed up, weather was around 42 degrees), and the check engine light came back on. I pulled over into a parking lock and pulled out my scanning tool and shut off the truck, I restarted the truck and the check engine light was gone. I checked the code scanner and all that was there was a pending code of p0305 for a misfire. I cleared the codes and nothing has come up since.  All three times that this has happened, I felt no misfire or loss of power from the engine. The code has disappeared every single time. My question is, is this something I should worry about? Should I take this to a mechanic even though nothing seems to be running wrong with the truck? I will also attach a video of the truck idling. 

truckrunningaudio.m4a

Edited by Buzz1
CamGTP Senior Enthusiast

CamGTP

Posted
Posted (edited)

Yes, it's still a problem that you should be worried about. The light wouldn't be coming on if this wasn't a problem.

 

Could be as simple has a failing spark plug or plug wire. Other things could be a fuel injector issue.

Edited by CamGTP
Buzz1 Enthusiast

Buzz1

Posted
  • Author
Posted
11 minutes ago, CamGTP said:

Yes, it's still a problem that you should be worried about. The light wouldn't be coming on if this wasn't a problem.

 

Could be as simple has a failing spark plug or plug wire. Other things could be a fuel injector issue.

Would it be possible for it to be one of those options if there is no detectable difference in the engine running or driving when the misfiring is occurring / make the issue intermittent, or because of that is it more likely a bad sensor? If so, what sensors would go bad and cause a false flag for a misfire. 

ftwhite Enthusiast

ftwhite

Posted
Posted (edited)

If you didn't feel the misfires, it's much more likely a bad crank position sensor. That's what the ecu uses to calculate a misfire. It expects the crank to accelerate and decelerate in an exact pattern based on cylinders firing. When it gets this wrong repeatedly, it reports the misfire. It's not hard or expensive to replace, so start there (imo).

Edited by ftwhite
Lsgun1 Enthusiast

Lsgun1

Posted
Posted

Have you changed plugs and wires ever? Start simple don't go replacing sensors, the computer picks up a misfire a lot faster then you do.

newdude Senior Enthusiast

newdude

Posted
Posted
On 3/15/2021 at 11:43 PM, Buzz1 said:

Hello,

 

I have a 2016 Silverado LTZ (8 Speed, 5.3) with around 110,500 miles currently.  Earlier, back in December (107,339 Miles) after the truck had sat for a couple of days, I was driving down the flat highway (Going around 72) and all the sudden I noticed a flashing check engine light. I pulled over and then the light turned steady. I called onstar and they informed me that it was a engine missfire, since the light was no longer flashing I continued to drive. 

 

There was a pending code of P0305 for a misfire in cylinder 5.  The weather during that drive was clear but very cold, around freezing. The engine never fully warmed up. I thought it was just a random issue, or bad fuel until this evening. I was driving going around 40 miles per hour, (Engine fully warmed up, weather was around 42 degrees), and the check engine light came back on. 

truckrunningaudio.m4a 310.79 kB · 3 downloads

 

 

Ever had any fuel injectors replaced yet?  May or may not set a P050D as well.  

  • Like 1
Logan Lanfear Enthusiast

Logan Lanfear

Posted
Posted

Change all the plugs, after 115k its probably time. Go with OEM or something quality. If you don't know how to read plugs then post a picture of all 8 on here and we can tell you how they look. While you're there, changing the wires isn't a bad idea either. 

Its a good time for a tune up. If it doesn't fix the issue then you can look deeper into injectors or CPS. Its a good time to change the plugs anyway. 

Buzz1 Enthusiast

Buzz1

Posted
  • Author
Posted
On 3/17/2021 at 11:23 AM, Logan Lanfear said:

Change all the plugs, after 115k its probably time. Go with OEM or something quality. If you don't know how to read plugs then post a picture of all 8 on here and we can tell you how they look. While you're there, changing the wires isn't a bad idea either. 

Its a good time for a tune up. If it doesn't fix the issue then you can look deeper into injectors or CPS. Its a good time to change the plugs anyway. 

 

I just had all the plugs and wires replaced by the dealer at around 103,000 miles. One of my good friends and I checked out the spark plug on the cylinder with the issue and it looks fine, but it was a little bit looser than the other plugs. We tighten it put it back in, and switched its wire with another one from a different cylinder, we are going to see what happens then. 

 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Chuck FB
      first oil change - 2026 2500HD gas

      By Chuck FB · Posted

      Indeed a proper drain tap or drain valve with adapter that has a hose on it that opens up the valve as the adapter goes on is a slick setup and have that for certain highway tractors etc and other equipment that came from the factory with a tap but this L8T is pretty darned good other than me doing it on the floor and easy to touch hot exhaust and am not as agile as I used to be !. If I really want to pull a hot filter on an engine I will use an insulated set of thick neoprene gauntlet gloves but I am not in the hurry I used to need to be so things are done more relaxed and in theory somewhat safer ... I think LOL.    And as I mentioned the unique shape of the Amsoil 1 quart containers, while they might not work as well as an offset pour spout container for some awkward engine location applications, they are working a lot better with my Lisle funnel kit because of how they prop up on all four corners when upside down resting on the rim of the funnel where the typical quart container would never stay put without holding onto it. 
    • mrbflat
      Clunk when coming to a stop... driveshaft/slip yoke? Mechanic couldn't recreate it

      By mrbflat · Posted

      Well, I just hit 100K a few weeks back, and I can honestly say I have not had any major issues with my '21 5.3 Crew cab.  I have done most routine maintenance, oil changes, air filter, tire rotations, and a transmission drain and filter change (not even a full flush).  A couple of months ago, I started experiencing the dreaded CLUNK when coming to a stop, sometimes hard enough to literally push the truck forward! After researching here and in other forums/youtube videos, etc, I was thinking it's the slip yoke. I finally had a chance to take it to my local mechanic today, and he was not able to recreate the issue.  Amazing, since it does it nearly every time I drive.  He also said he can't simply grease my slip yoke/driveshaft splines, because I have a 1 piece driveshaft.  I am not sure what else I can do.  Has anyone else had this issue or have any idea what else it could be?
    • Black02Silverado
      first oil change - 2026 2500HD gas

      By Black02Silverado · Posted

      This is where the Fumoto drain valve comes in handy.  No mess and able to change oil hot, like right off the interstate hot.  Flows nice and you can direct it into a container. As for the oil filter, I use an old dixie cup or plastic one from McDonalds. It contains the oil as you pull the filter down and not all over your hand.
    • Black02Silverado
      Which 2027 engine will you choose?

      By Black02Silverado · Posted

      Well, if it did change from lifters to rocker arms, at least it would be easier to fix as they fail.
    • Black02Silverado
      HighMileage oils or stay with Dexos 1 ?

      By Black02Silverado · Posted

      Doesn't hurt to try.  It's my understanding that you have to run it at least 4 or 5 oil changes for things to get clean.  Think about it, your engine didn't get dirty in just an oil change so over time it will slowly clean. It's the safest way to do it and not have seal issues.      I remember  a product that came out a long time ago, AutoRX, it was an additive you put in the oil and then drove for 3k miles. Some saw improvements and some didn't. It was suggested to use a non synthetic with it at the time. Same observation, use a couple oil changes and give it time to work. It also stated it worked best if you could drive on trips to keep the oil hot.  I'm sure if you ask AI it could tell you all about it.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...