P0284 on Ford
Cylinder 8 Contribution/Balance Fault
P0284 on Ford vehicles indicates cylinder 8 contribution/balance fault. Au7o has documented this code across 2 Ford models — most commonly on F-250 Super Duty, F-350. The PCM determined cylinder 8 is not contributing its expected share of power/fuel relative to the other cylinders. Indicates an injector flow imbalance, low compression, or fueling problem on cylinder 8. Typical repair costs on Ford range from $900 to $5,000, depending on the specific model and root cause.
Common Causes of P0284
- •Restricted, leaking, or weak cylinder 8 injector
- •Low compression on cylinder 8
- •Injector wiring/connector fault
- •Mechanical issue on that cylinder
- •Fuel delivery imbalance
P0284 on Ford by Model
Ford F-250 Super Duty(1 issue)
- 6.0L Power Stroke HEUI Injector Stiction - Spool Valve Sticking on Cold Start2003-2007
Each 6.0L HEUI injector contains two spool valves actuated by high-pressure engine oil. Oil varnish, coking and wear cause the spool to stick - 'stiction' - so the injector cannot respond to the FICM's command quickly enough. The signature is unmistakable to owners: a hard cold start followed by a shaking, misfiring, smoky idle for the first few minutes that disappears once the oil warms and thins. Cylinder contribution and injector on-time data will show one or more cylinders far out of range. Extended oil change intervals and the wrong oil grade accelerate it, and the 6.0's oil is doing double duty as hydraulic fluid, which is why oil quality matters far more here than on a conventional diesel.
Ford F-350(1 issue)
- 6.0L HEUI Injector Stiction - Cold-Start Misfire from Varnished Spool Valves2003-2007
The 6.0L Power Stroke uses hydraulically actuated, electronically controlled unit injectors (HEUI) that are fired by high-pressure engine oil. Oxidized oil leaves a varnish film on the injector spool valve, and when the engine is cold that film creates static friction (stiction) that keeps the spool from moving on command. The result is a dead or lazy cylinder for the first minutes after a cold start, clearing as oil warms. Owners report a rough, shaking cold start that smooths out after several miles and then progressively worsens over months until the injector fails outright. Extended oil-change intervals, low-quality oil and short-trip use all accelerate it. This is an oil-side failure mode of the HEUI system and does not apply to the 6.4L or 6.7L, which use common rail.
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View P0284 across all makes →Frequently Asked Questions
What does P0284 mean on Ford?▼
P0284 stands for "Cylinder 8 Contribution/Balance Fault." The PCM determined cylinder 8 is not contributing its expected share of power/fuel relative to the other cylinders. Indicates an injector flow imbalance, low compression, or fueling problem on cylinder 8. On Ford specifically, this code is documented across 2 models.
What causes P0284 on Ford vehicles?▼
Common causes on Ford: Restricted, leaking, or weak cylinder 8 injector, Low compression on cylinder 8, Injector wiring/connector fault, Mechanical issue on that cylinder, Fuel delivery imbalance. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0284 on a Ford?▼
Repair costs on Ford range from $900 to $5,000, depending on the specific model and root cause.
Which Ford models have P0284 documented?▼
Au7o has documented P0284 on 2 Ford models: F-250 Super Duty, F-350.