5 Reasons Your Truck’s Engine Is Losing Power

A loss of engine power in your heavy-duty truck costs you time, lowers fuel efficiency, and can disrupt your schedule, leading to a drop in customer satisfaction. Whether you're climbing steep grades in Hudson, New Hampshire, or cruising long hauls across state lines, your truck needs full power to perform at its best! 

If your engine is struggling, here are five possible reasons why and how to fix them.

1. Clogged Fuel Filters

Your truck's fuel filter keeps contaminants out of the fuel system, ensuring a steady flow of clean diesel to the engine. Over time, dirt, debris, and sludge can clog the filter, restricting fuel flow and reducing engine power.

Symptoms of a Clogged Fuel Filter:

• Engine sputtering or stalling
• Slow acceleration, especially under load
• Decreased fuel efficiency

How to Fix It:

• Replace fuel filters at the manufacturer’s recommended intervals (typically every 15,000–25,000 miles).
• Use high-quality diesel fuel to minimize contaminants.
• If your truck has a fuel/water separator, drain it regularly to prevent water buildup.

2. Failing Turbocharger

A turbocharger forces more air into the engine, increasing power and efficiency. If the turbo fails, your engine won't get enough air, causing a significant drop in performance.

Signs of Turbocharger Issues:

• Loss of power, significant when accelerating or climbing hills
• Excessive black smoke from the exhaust
• Whining or whistling noise from the turbo

How to Fix It:

• Inspect turbo hoses and clamps for leaks or cracks.
• Clean or replace air filters to prevent dirt buildup.
• If the turbocharger fails, a professional inspection and replacement may be necessary.

3. Air Intake Restrictions

Your engine relies on proper airflow to mix with fuel and produce power. If the air intake system is restricted, your truck won't perform as it should.

Common Causes of Airflow Problems:

• Dirty or clogged air filters reduce airflow
• Blocked intercoolers prevent proper cooling of intake air
• Malfunctioning mass airflow sensors (MAF) causing incorrect air-fuel ratios

How to Fix It:

• Replace air filters every 30,000–50,000 miles (or sooner in dusty environments).
• Check and clean intercoolers to remove debris.
• If the MAF sensor is faulty, have it tested and replaced.

4. Fuel Injector Problems

Fuel injectors deliver diesel into the combustion chamber at precise amounts and pressure. If they clog, leak, or fail, your engine won't get the correct fuel mixture, leading to power loss.

Symptoms of Bad Fuel Injectors:

• Rough idling or engine misfires
• Noticeable drop in fuel economy
• Increased exhaust smoke (white or black)

How to Fix It:

• Use diesel fuel additives to clean injectors and prevent buildup.
• Have injectors tested and professionally cleaned if performance issues persist.
• Replace injectors if they are leaking or damaged.

5. Exhaust System Restrictions (DPF & EGR Problems)

Modern diesel engines use after-treatment systems like the Diesel Particulate Filter (DPF) and Exhaust Gas Recirculation (EGR) to reduce emissions. If these components become clogged or fail, they can strangle engine performance.

Common Exhaust System Issues:

• DPF clogging restricts exhaust flow, forcing the engine to work harder.
• EGR valve failure recirculates too much exhaust gas, causing sluggish performance.
• Exhaust leaks can reduce turbo efficiency.

How to Fix It:

• Perform DPF regeneration regularly to burn off soot buildup.
• Clean or replace EGR valves if they are sticking or clogged.
• Inspect the exhaust system for leaks or cracks and repair as needed.

How to Prevent Engine Power Loss

To keep your semi-trucks engine running at peak performance, follow these maintenance steps:

Regular Fuel System Maintenance: Change fuel filters and use clean diesel.

Air Intake Inspections: Replace air filters and check for blockages.

Turbocharger Monitoring: Inspect for leaks and strange noises.

Exhaust System Checks: Keep the DPF and EGR systems clean.

Diagnostic Scans: Run regular engine diagnostics to catch small issues before they become big problems.

Final Thoughts

If your truck is losing power, don’t ignore the warning signs. Whether it's a clogged filter, failing turbo, or fuel injector issue, diagnosing and fixing the problem early can save you from costly downtime. If you need engine diagnostics, turbo repairs, or fuel system maintenance in Hudson, NH, stop by Redmond Service Center for expert service.