The Lemon IndexThe engine computer sees misfires that move around between cylinders instead of staying in one. Full P0300 page
10 owner complaints · the #6 code GMC Sierra owners name · 5% of GMC Sierra complaints that name a code (every car: 2.9%)
2011–2021 GMC Sierra · most: 2021 (2), 2020 (2), 2019 (2)
GMC Sierra owners named P0300 in 10 complaints to the U.S. government (NHTSA), most often on the 2021, 2020 and 2019 model years. The part they name most is the fuel injectors (3 complaints). Complaints are owner reports, not proof of a defect.
GMC Sierra model years that report P0300
Owner complaints naming P0300, by model year. Raw counts: years that sold more get more complaints, so this is each model year's record, not a failure rate.
What owners say caused it or fixed it
The most-named part is the fuel injectors, in 3 of the 10 complaints (30%). 2 of those mention it being replaced or repaired, and 1 say the problem came back afterwards.
- Fuel injectors3 complaints2 mention a repair or replacement, 1 of them says the problem came back · what GMC Sierra owners paid
Counted from the owners' own words: a part counts when a sentence names it with a cause or repair word. What owners wrote, not a diagnosis. A shop should confirm the cause before replacing parts.
Symptoms owners describe with P0300
60% of these complaints say the check engine light came on.
- Loses power or goes into limp mode60%6 of 10 complaints
- Shakes, runs rough or misfires50%5 of 10 complaints
- Rattles or knocks30%3 of 10 complaints
Share of the complaints naming P0300 whose text also describes each problem. A complaint can describe more than one.
Codes owners report with it
P0302 2
Other codes named in the same GMC Sierra complaints, and in how many.
Repair costs
GMC Sierra fuel injector replacement cost
Recalls on these GMC Sierra years
- Engine · 2021 · issued 2025
The connecting rod and/or crankshaft engine components may have manufacturing defects that can lead to engine damage and engine failure. NHTSA 25V274000
1 recall for the same systems (engine) on the GMC Sierra model years above. A recall for the same system isn't proof it's behind P0300. Recall work is free at any dealer: check a VIN at nhtsa.gov/recalls or with our VIN check.
Keep going
- P0300: meaning, causes and every car that reports it
- GMC Sierra reliability by year
- 2021 GMC Sierra problems and recalls
Other codes GMC Sierra owners report
P0300 on other cars
Ford Escape (36) · Chevrolet Silverado (19) · Ford Fusion (19) · Honda Accord (14) · Honda CR-V (14) · Kia Soul (14) · Ford Edge (13) · Chevrolet Tahoe (11) · Ford F-Series (10)
The details
How we count
We read every owner complaint in the NHTSA file whose text names this trouble code, and count the ones filed about this model (matched by the make, model and model year on the complaint). Mileage is what the owner entered on the form.
Parts: a complaint counts for a part when one of the owner's own sentences names that part together with a cause word (failed, bad, diagnosed, caused by, leaking ...) or a repair word (replaced, repaired, new, reprogrammed ...). "Came back" means the same complaint also says the problem returned or the repair didn't fix it. These are counts of what owners wrote, not a diagnosis, and one complaint can name several parts.
Complaints are reports, not proof of a defect, and most owners never file one. Popular models get more complaints, so the counts are not a failure rate. The code meaning is the standard SAE J2012 definition in our own words, or the carmaker's meaning where we verified it for that make.
What P0300 means
The engine computer sees misfires that move around between cylinders instead of staying in one. The engine may shake, stumble or feel down on power. If the check engine light flashes, the misfire is bad enough to overheat the catalytic converter: slow down and get it checked right away.
Get it fixed soon. A few more days of normal driving is usually OK, but waiting can turn a small repair into a bigger one or a breakdown.
- Worn spark plugs or ignition coils
- Vacuum leak
- Low fuel pressure or dirty injectors
- Engine mechanical problem (compression, valve timing)
Check the complaints yourself
NHTSA complaint numbers (search them at nhtsa.gov): 11759795, 11706741, 11700630, 11657834, 11546655, 11517362, 11442943, 11431645, 11361352, 11151017.
Quick answers
What does P0300 mean on a GMC Sierra?
Random/Multiple Cylinder Misfire Detected. The engine computer sees misfires that move around between cylinders instead of staying in one. The engine may shake, stumble or feel down on power. If the check engine light flashes, the misfire is bad enough to overheat the catalytic converter: slow down and get it checked right away.
Which GMC Sierra years have the most P0300 complaints?
In complaints to NHTSA, owners of the 2021 (2), 2020 (2), 2019 (2) GMC Sierra named P0300 most (10 complaints in all, 2011–2021). Raw counts, not a failure rate.
What fixes P0300 on a GMC Sierra?
Owners most often name the fuel injectors (3 of 10 complaints). That's what owners wrote, not a diagnosis: have a shop confirm the cause with a scan and tests before replacing parts.
Can I drive my GMC Sierra with P0300?
Get it fixed soon. A few more days of normal driving is usually OK, but waiting can turn a small repair into a bigger one or a breakdown.
Sources: NHTSA owner complaints that name P0300 on the GMC Sierra, counted by The Lemon Index; NHTSA recalls; repair bills owners named. Meanings: SAE J2012 in our own words. Owner reports, not a diagnosis or repair advice for your car.