The 6.0L Power Stroke (Ford, 2003–2007) uses a HEUI injection system — injectors fired by high-pressure oil and controlled by the FICM (Fuel Injection Control Module). When a 6.0L runs rough or won't start, the cause is often one of these two systems, and telling them apart saves you from replacing the wrong part.

Symptoms that point to the injectors

• Rough idle or a steady miss, often worse at cold start ("stiction" from sticky injector spool valves).
• White smoke and a hard cold start that improves as the engine warms.
• Knock or rattle from one or more cylinders.
• Fuel in the oil or rising oil level.

Symptoms that point to the FICM

• Hard or no start when cold, sometimes improving once warm.
• Multiple-cylinder misfire that appears all at once (rather than one stubborn cylinder).
• Buzzing from the FICM or a measured FICM power voltage below spec (healthy is around 48 volts).

A weak FICM can't drive the injectors properly, which mimics injector failure — so check FICM voltage before condemning injectors.

How to diagnose it

1. Scan for codes and look at injector/cylinder contribution data. Single-cylinder issues lean toward an injector; symmetrical, multi-cylinder issues lean toward the FICM or oil supply.
2. Measure FICM power voltage at key-on and during cranking; low or unstable voltage indicates a failing FICM.
3. Check ICP (injection control pressure) and the high-pressure oil system — a HEUI engine won't run right without adequate oil pressure to fire the injectors.
4. Confirm oil level/quality — diluted oil suggests a leaking injector.

Repair notes

6.0L injectors are commonly serviced as a set, and stiction-related issues sometimes respond to proper oil and additives — but mechanical failure requires replacement. A failed FICM is replaced or rebuilt as a unit.

Before you order: 6.0L injectors and FICMs vary by year and build. Verify the exact part by OEM cross-reference for your truck before purchasing.

See options on our 6.0 Power Stroke collection and fuel injector catalog, or contact us with your VIN/engine details for help confirming the right part.