p0300 misfire code

[TexasBaseballDAD]

On 6/11/2021 at 6:58 PM, Mobud said:

Did switching gas help with the misfire? My 21 Sierra has done it twice now dealer found p300.

I have a 21 AT4 5.3 V8, and I've had the check engine come on showing the same code, however, it went away.  I recently took a long trip, filled up at a local Walmart after I got back in town.  Fast forward a few days and my truck has developed a bit of a shake when driving, along with a bit of a slip when coming to a stop, along with check engine light flickering some.  Not sure if you have had the same symptom, but I am curious if I put a bad batch of gas in my truck.  Was curious if you have experienced the same.  

[Mobud]

So I thought too maybe it was bad gas. Took to dealer once had generic 300 code then light flashed again stopped by dealership said it was same code so a tech went and go scan took I had misfires on 1&6 said they’ve had a lot of issue with the lifters collapsing due to a bad batch of parts. So next week they’re replacing all lifters.the tech also said usually by 5000 miles they will fail I’ve got 2700 on mine.

Edited June 16, 2021 by Mobud

[Belo]

this happened to me a few weeks ago and then shutoff later the next day. mine was unsettling as it came on while driving through some fields (hey it's a truck right?) nothing reckless, just pulling a turkey blind. Never noticed any performance issues but for having less than 10k on the odometer and just 2 years old... 

[Enmoyer]

Joining the 0300 club. Trail Boss that is 3 days old! WTAF

[Mobud]

So I’ve had both banks of lifters replaced in mine at about 2500 miles. Went another 2500 check engine light came back on supposedly had to relearn the cam shaft position sensor. Lasted two weeks came back on apparently they are waiting for GM to rewrite code but they can’t figure out how to fix the issue and that was a month ago with still no update. Good luck

[usmcav8or]

I have a week old 1500 AT4, just threw the P0300 code with 967 miles on the truck, this is my very first GM product, holy crap, why can't American companies build a reliable product?!!  I don't want to drive a Japanese truck, but damn it, American cars are so freaking awful    I don't have time in my life to take cars to dealers, if this keeps happening, it's back to Toyota (where I NEVER had a single freaking issue with two of them in over 250,000 miles combined!)

[Ed tha man]

I'm following this thread.  My 2020 Sierra started with the check engine light flashing for 10 seconds.  Dealer puller the p0300 code.  The next day the truck shook with the check engine light and service ECS system.  Restarted the truck it went way.  Too bad I'm at 37K with just over one year of ownership.