P0300 — Random / Multiple Cylinder Misfire (Chery Context)
Standard meaning: the ECU detected misfires across multiple cylinders with no single culprit. On Chery’s all-turbo, all-direct-injection range the usual suspects are ordinary — plugs, coils, fuel quality — but the order of checking changes when the whole fleet is young and under warranty.
What it means on your Chery
| If you drive… | Context | First move |
|---|---|---|
| Tiggo 7 Pro 1.6T (2023–25) | This engine is specified for 95 RON; sustained 91/E10 on a hot day is a classic misfire recipe on DI turbos. | Confirm what’s actually been going in the tank; run a tank of the right fuel before any parts. |
| Tiggo 4 / new Tiggo 7 1.5T (91 RON) | Fuel grade is less likely the story; ignition service items and injector cleanliness lead. | Check service history against schedule — plugs on time? |
| Super Hybrid (plug-in) models | The petrol engine can sit unused for weeks on short-trip EV driving — stale fuel and infrequent engine cycles are documented hybrid-family behaviours. | Note the driving pattern for the dealer; it changes their diagnosis. |
Safe owner checks
- Fuel: grade and age. A plug-in that’s barely burned petrol in months is running on old fuel.
- Rough idle only when cold, or all the time? Note it — freeze-frame gold.
- Service history: plugs and filters on schedule?
When it’s a workshop job
Flashing check-engine light = active misfire damaging the catalyst — stop driving hard, get it seen. Steady light with recurring P0300 inside warranty: dealer, documented, free. Out of warranty: compression/leak-down and coil swap-testing are workshop work on a DI turbo — the parts-cannon approach costs more than the diagnosis.
Code definition per SAE J2012. Fuel-grade specifics from our GVG-verified consumption records (95 RON Tiggo 7 Pro vs 91 RON successors) — the two-generation split is documented on our corrections page.