P0284⛽ Fuel injection / cylinder balanceStop and fix promptly

P0284: Cylinder 8 Contribution/Balance (Meaning, Causes, Fixes)

Reviewed 2026-10-25 · Based on 2 cited source(s)

What P0284 means

The engine computer (PCM) watches how much the crankshaft speeds up during each cylinder's power stroke. OBD-Codes.com explains that when a cylinder adds less acceleration than the rest, the PCM sets a contribution/balance code for that cylinder, and P0284 is the one for cylinder 8 (OBD-Codes.com describes it as the number eight cylinder in the firing order). OBD-Codes.com says this points to a fuel-related problem in that cylinder, and that a purely electrical injector fault would normally set a separate high or low voltage code for that injector instead. RepairPal describes it more generally: the PCM has detected that cylinder 8 is not contributing enough to keep the engine running properly. The code is generic to OBD-II vehicles, but searches for it often mention Ford Power Stroke diesels (7.3L, 6.7L, 6.0L and 6.4L) and GM Duramax diesels, and repair steps vary by make and model, so check technical service bulletins (TSBs) for your vehicle.

Severity: can I keep driving?

Stop and fix promptly

Get it diagnosed soon. RepairPal rates P0284 'Urgent', meaning it can cause severe damage, and OBD-Codes.com says it should be addressed at your earliest convenience to prevent damage. A cylinder that isn't pulling its weight can run rough and lose power. If the check engine light is flashing, the engine shakes badly, or you smell raw fuel or see heavy smoke, keep driving to a minimum and have it checked. Fuel systems run under high pressure, especially on diesels, so don't open fuel lines with the engine running and let the engine cool before working near it.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. Dirty, clogged or dribbling cylinder 8 fuel injector, for example from dirt or contamination of the injector inlet filter (OBD-Codes.com says lack of fuel to cylinder 8 is the most likely cause)
  2. Failed cylinder 8 fuel injector (listed by both sources)
  3. Corroded terminals or pushed-out pins in the injector connector (listed by OBD-Codes.com)
  4. Wiring problem (listed by RepairPal)
  5. Internal engine problem in cylinder 8 (listed by RepairPal)
  6. Engine computer (PCM) software that needs updating (listed by RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Read all stored codes. Note any cylinder 8 injector circuit codes such as P0208 or misfire codes such as P0308, since they help narrow down the cause.
  2. Look up technical service bulletins for your year, make and model, as OBD-Codes.com recommends.
  3. Inspect the cylinder 8 injector connector and the harness side for corrosion, bent or pushed-out pins. Fix any damage and add dielectric grease before reconnecting.
  4. On a gasoline engine, OBD-Codes.com suggests listening to the injector with a long screwdriver (handle to your ear) while the engine runs. A steady ticking means it is firing; no ticking means no power or a dead injector.
  5. Clear the code and drive. If the rough running and the code come back after the connector checks out, the injector likely needs cleaning or replacement.

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • OBD-Codes.com notes a power-balance test (pulling one spark plug wire at a time and watching the RPM drop) can find weak cylinders, and says all cylinders should be within 5 percent of each other
  • OBD-Codes.com says a supply voltage check at the injector should show battery voltage; no voltage means an open circuit between the injector and the fuel pump relay
  • The sources differ on causes: OBD-Codes.com focuses on the injector and its connector, while RepairPal also lists internal engine failure, wiring and a PCM software update
  • Diesel engines (such as Ford Power Stroke and GM Duramax) have high-pressure injection systems; injector testing and replacement on those is best left to a shop with the right scan tool
  • The code returns after injector cleaning or replacement, or other cylinders also set contribution/balance codes

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with P0284?

Only as much as you need to. RepairPal rates it 'Urgent', and OBD-Codes.com says to address it at your earliest convenience to prevent damage. If the engine shakes badly or the check engine light flashes, limit driving and get it checked.

Is P0284 always a bad injector?

No, but it's the most likely cause. OBD-Codes.com says a lack of fuel to cylinder 8, from a clogged, dribbling or failed injector, is the most likely cause. RepairPal also lists wiring, internal engine failure and a PCM software update, so check the connector and test before buying parts.

What's the difference between P0284 and P0208?

P0208 is an electrical fault in the cylinder 8 injector circuit. P0284 means cylinder 8 is making less power than the others, which OBD-Codes.com says usually points to a fuel delivery problem rather than a high or low voltage fault.

Why do searches for P0284 mention Power Stroke and Duramax diesels?

Our sources don't give a reason specific to those engines; both describe P0284 as a generic code. Search suggestions for P0284 often name the 7.3L, 6.7L, 6.0L and 6.4L Power Stroke and the Duramax, so check for TSBs for your vehicle and have a diesel shop test the injectors with the right scan tool.

Sources

  1. OBD-Codes.com: P0284 Cylinder 8 Contribution/Balance (Don Bowman, ASE)
  2. RepairPal: P0284 OBD-II code (rated Urgent)

Last reviewed 2026-10-25. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.