Cylinder 8 Contribution/Balance Fault
The P0284 code means the vehicle's onboard diagnostic system has detected: Cylinder 8 Contribution/Balance Fault. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $600 (parts and labor)
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Common Symptoms
- Engine misfire on cylinder 8
- Rough idle and vibration
- Check Engine Light illuminated
- Uneven power delivery
- Engine shakes especially at idle
Probable Causes (Ranked by Likelihood)
- Faulty cylinder 8 fuel injector (incorrect fuel delivery) Very High
- Low compression in cylinder 8 High
- Leaking or clogged injector on cylinder 8 High
- Vacuum leak at cylinder 8 intake runner Moderate
- Worn camshaft lobe affecting cylinder 8 valves Low
Frequently Asked Questions
Can I drive with code P0272?
You can drive short distances with light loads. Cylinder 8 is producing less power than normal, and the engine will run rough. Avoid towing until repaired.
Is P0272 always a serious problem?
Not always. It could be as simple as a clogged injector that needs cleaning. However, low compression or a worn camshaft lobe would indicate a more serious mechanical issue requiring significant repair.
Can fuel quality cause a contribution fault?
Contaminated or low-quality fuel can cause injector clogging and uneven fuel delivery, which may trigger contribution codes. Using quality fuel and periodic injector cleaning can help prevent this.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Perform a cylinder contribution test using a scan tool to compare each cylinder's output
-
Run a compression test -- cylinder 8 should be within 10% of the highest cylinder
-
Swap cylinder 8 injector with another cylinder to determine if the injector is the cause
-
Check for vacuum leaks at cylinder 8 intake port using a smoke machine
-
If compression is low, perform a leak-down test to identify the failure point
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
P0284 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
Commonly Affected Vehicles
- 2010-2020 Ford Mustang GT (5.0L V8)
- 2012-2019 Chevrolet Corvette (6.2L V8)
- 2008-2018 Dodge Charger (5.7L HEMI)
- 2011-2020 GMC Sierra (5.3L V8)
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