P0266 on Ford
Cylinder 2 Contribution/Balance Fault
P0266 on Ford vehicles indicates cylinder 2 contribution/balance fault. Au7o has documented this code across 2 Ford models — most commonly on F-250 Super Duty, F-350. P0266 is a generic powertrain code indicating the engine computer detected that cylinder 2 is not contributing its expected share of power, meaning its output is unbalanced compared to the other cylinders. The PCM monitors crankshaft acceleration and fuel/injector behavior per cylinder, and an imbalance here often signals a misfire, fuel-delivery, or mechanical problem specific to cylinder 2. Left unaddressed, this can cause rough running, poor performance, and possible catalytic converter damage. Typical repair costs on Ford range from $900 to $5,000, depending on the specific model and root cause.
Common Causes of P0266
- •Faulty or clogged fuel injector on cylinder 2
- •Injector wiring or connector fault
- •Ignition fault (coil, plug) causing a cylinder-2 misfire
- •Low compression / mechanical issue (valve, ring) on cylinder 2
- •Vacuum or intake leak affecting that cylinder
- •Contaminated or restricted fuel supply
- •PCM driver circuit fault for that injector
P0266 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 P0266 across all makes →Frequently Asked Questions
What does P0266 mean on Ford?▼
P0266 stands for "Cylinder 2 Contribution/Balance Fault." P0266 is a generic powertrain code indicating the engine computer detected that cylinder 2 is not contributing its expected share of power, meaning its output is unbalanced compared to the other cylinders. The PCM monitors crankshaft acceleration and fuel/injector behavior per cylinder, and an imbalance here often signals a misfire, fuel-delivery, or mechanical problem specific to cylinder 2. Left unaddressed, this can cause rough running, poor performance, and possible catalytic converter damage. On Ford specifically, this code is documented across 2 models.
What causes P0266 on Ford vehicles?▼
Common causes on Ford: Faulty or clogged fuel injector on cylinder 2, Injector wiring or connector fault, Ignition fault (coil, plug) causing a cylinder-2 misfire, Low compression / mechanical issue (valve, ring) on cylinder 2, Vacuum or intake leak affecting that cylinder. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0266 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 P0266 documented?▼
Au7o has documented P0266 on 2 Ford models: F-250 Super Duty, F-350.