P02A8
Cylinder 4 - Injector Restricted
Fuel & air metering
Generic OBD-II
High
What it means
P02A8 means cylinder 4's fuel injector is flowing less fuel than commanded — it's partially clogged or restricted. The ECM detects that cylinder 4 needs more fuel than it can deliver, so that cylinder runs lean and may misfire, especially under load.
High
Can I keep driving? Driveable, but a restricted cylinder 4 injector leans out and misfires that cylinder; fix it before long trips.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or misfire on cylinder 4
- Hesitation and reduced power under load
- Possible hard starting
Common causes
Most likely first
- Clogged or restricted cylinder 4 injector (deposits)Likely
- Poor-quality or contaminated fuelCommon
- Low fuel pressure or a restricted fuel filterCommon
- Wiring or connector fault on the injector (less likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame and confirm which cylinder is affected.
- Check fuel pressure and filter condition.
- Run an injector-balance or flow test on cylinder 4.
- Try a quality injector cleaner; if flow is still low, clean or replace the cylinder 4 injector.
- Clear the code and re-test under load.
FAQ
Quick answers
Is it safe to drive with P02A8?+
It's driveable, but a restricted injector leans out and misfires cylinder 4, which can damage the converter over time. Fix it before long trips.
Can I just clear P02A8?+
It returns once the ECM again sees cylinder 4 short on fuel; the injector needs cleaning or replacement.
Related codes
Often seen with P02A8
Read & clear P02A8 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX