P0300 on GMC vehicles
30 owner complaints filed with NHTSA about GMC vehicles mention P0300 (Random/Multiple Cylinder Misfire Detected) - across 6 models. Below is where it shows up, by model and year.
Can you drive with it? Short trips at moderate speed are usually tolerable; a flashing check engine light means stop - raw fuel is destroying the catalytic converter.
Symptoms, likely causes in order and realistic repair costs are on the main P0300 page - they do not differ much by brand. This page shows what is specific to GMC: which models and years actually report it.
GMC models reporting P0300
The number next to each year is how many NHTSA complaints for that car mention P0300. Owners rarely quote trouble codes when complaining, so real occurrence is many times higher - use these numbers to compare years, not as totals.
What GMC owners report
“I got the vehicle with 60,000 miles 8,000 miles in vehicle gave me problems gave me a check engine light code p0300 then took it to get inspected then was told it was the fly wheel then it's started knocking vehicle is currently not being droven because of the fly wheel”2022 GMC Sierra 1500 · Aug 2026
“Misfire on 2 cylinder, noise on start up diagnostic code P0300 P0302 P050 I was driving home and the engine started making a strange sound, vehicle would could no increase speed normally. The dealership did basic analysis from the onboard computer and did a compression test. Heavy knocking sound on passenger side of the engine. The issue happened on Aug 5th 2026. The issue is due to the AFM that causes the lifter to fail and dealership says I need a new engine $15787 or replace cam shaft $14530.”2020 GMC Sierra 1500 · Aug 2026
P0300 on other makes
Makes with enough NHTSA reports of P0300 for their own page.
Counts are NHTSA owner complaints whose text mentions P0300 - owner-reported and unverified. Always confirm with a diagnosis of your specific vehicle.