Causes and Solutions of P0087 Duramax Code

Code P0087 is a recurring issue I often encounter in my experience with Duramax vehicles. This code usually points to low fuel rail pressure, which signifies that the engine isn’t receiving the necessary fuel. Code P0087 Duramax can be a cause of concern for many vehicle owners, and this may seem straightforward, but it’s a complex problem that requires thorough investigation.

I can handle such complications and provide effective solutions for restoring optimal engine performance.

What is P0087 Code?

Causes and Solutions of P0087 Duramax Code

The P0087 code is a diagnostic trouble code that indicates an issue with the fuel rail pressure system and occurs when the fuel rail pressure is lower than what has been specified by the manufacturer.

This error occurs when the fuel supply to the injector is lower than the standard level. As a result, the oil supply to the injectors becomes insufficient, causing them to malfunction. 

Duramax Fuel Rail Pressure Specifications:

To understand why a P0087 code is triggered, it’s essential to know the fuel rail pressure specs for a Duramax. 

Minimum CrankingMinimum IdleMax Running (Pre-2006)Max Running (2006-2010)Max Running (Post-2010)
1,500 PSI5,000 PSI23,000 PSI26,000 PSI29,000 PSI


This code can be frustrating, but understanding its symptoms can help you quickly diagnose and fix the issue.

  • The first symptom of a P0087 Duramax code is a decrease in GM engine power. This may manifest as sluggish acceleration or difficulty maintaining speed on hills or at higher speeds.
  • A second symptom is rough idling or stalling when coming to a stop if you may notice an increase in black smoke coming from your exhaust or even an unusual odor as unburned fuel exits your system.

All Causes and Solutions of Code P0087 Duramax:

There are many causes of the Duramax P0087 code, but thankfully there are solutions available. Whether you have an LBZ, LB7, LML, LMM, or LLY engine, these causes and solutions are applicable to all Diesel engines.

There are seven potential causes for this code to appear on your OBD scanner, which we will discuss briefly.

Faulty Fuel Pump:

At its core, this code means that there is low fuel pressure in the system. This can be caused by a faulty fuel pump. The pump may not be delivering enough fuel to keep up with demand or may be failing entirely, leading to reduced performance and potential damage to other components.

If you are experiencing Code P0087 on your Duramax engine, it’s crucial to address the problem as soon as possible. Ignoring this issue can lead to more significant problems down the road and potentially costly repairs.


Regarding warranty claims for fuel pump issues on GM vehicles engines, there’s no need to worry about being blamed for fuel contamination. The process is simple – replace the CP4 fuel pump with a brand-new one that can save you and your vehicles.

Contaminated Fuel:

Duramax 6.6L V-8 engines are designed to run on Ultra-low sulfur diesel and B20 biodiesel. These fuels are known for their high efficiency and low emissions, making them an ideal choice for eco-conscious drivers.

It’s important to note that contaminated diesel fuel can cause issues with the engine’s fuel pump. GM has stated that most C4 fuel pump failure is due to contaminated fuel diesel, so it’s crucial to ensure that the diesel you use meets the required standards.

The three primary types of diesel fuel contamination are water contamination, inorganic debris like dust, sand, rust, etc., and organic debris such as fuel breakdown, waste fuel, and microbial contamination.


It highly recommends finding a trustworthy gas station if you see any signs of fuel contamination. And for added peace of mind, using a fuel additive cleaner can do wonders in cleaning the diesel and making your fuel contamination-free.

Blockage in the Supply Oil Line:

The most common cause of this code is a blockage in the supply oil line. This blockage can lead to restricted flow and low pressure in the fuel system, causing the engine to shut down.

One of the first signs of a blocked oil line is a loss of power and acceleration. The engine may also become sluggish or unresponsive when trying to accelerate quickly. In some cases, the check engine light may come on, indicating that there is an issue with the fuel system. 


If you’re dealing with a fuel supply issue, don’t even try fixing the line. It’s not worth it. The only viable solution here is to replace the entire fuel supply rail. It may seem like a daunting task, but it’s the only way you’ll truly be able to solve the problem at hand. 

A Small Leak in the Oil Supply Line:

This error code indicates a small leak in the oil supply line. One of the primary symptoms of P0087 is stalling or hesitation while accelerating. Drivers may notice a decrease in fuel efficiency and overall power. 

If you own an ’04 Duramax, it’s essential to keep an eye out for any signs of this issue. The best way to prevent P0087 is by regularly checking your vehicle’s oil levels and ensuring that all components are functioning correctly. 


If you notice a leakage in your fuel supply rail, it is important not to try to cover it up. This may only make the problem worse and pose a serious safety hazard. Instead, it is recommended that you install a new fuel supply rail. 

Debris in the Fuel Rail:

Over time, dirt and sediment can accumulate in the fuel tank and eventually make their way into the engine’s fuel system. When this happens, it will cause blockages and restrictions that reduce fuel flow to key areas of your engine. 

These blockages will lead to low-pressure conditions and trigger codes like P0087.


To ensure a smooth and efficient fuel system, it is important to regularly clean the injectors. To do this, you will need to pull out the injectors from the fuel rail and use a fuel injector cleaning kit to flush them out. 

This process will help remove any unwanted debris and buildup from the fuel rail, allowing for better fuel flow and performance from your vehicle.

Faulty Fuel Pressure Regulator:

If you notice that your Duramax is struggling to pick up speed or feels sluggish when driving uphill, this could be caused by low fuel pressure. 

You may experience stalling or hesitation while driving as a result of insufficient amounts of fuel reaching the engine. These symptoms can be frustrating and potentially dangerous in certain situations.


To fix the issue with the fuel pressure, it is necessary to remove the faulty fuel pressure regulator and replace it with a new one. This process involves carefully disconnecting the old regulator, which is responsible for controlling the amount of fuel that enters the engine, and installing a new one in its place. 

Faulty Injectors:

The Duramax injector is one of the most reliable injectors on the market, lasting up to 200,000 miles without needing a replacement.

The possibility of encountering a faulty injector triggering the P0087 code within this period is very low. It’s so rare that it’s highly arguable and should not concern anyone using Duramax. While this may be true, we cannot ignore the potential risk altogether. 


A Duramax injector costs around $500 on average, which is already a significant expense. The actual cost comes from labor – replacing an injector typically requires several hours of work and specialized tools. The labor cost for replacing a Duramax injector can range from $800 to $1,200, depending on where you take your vehicle for repair.

What Should I Do If P0087 Code Pops Up in My Car?

If you are driving and suddenly notice the P0087 code pops up on your car’s dashboard, it can be quite scary. This code indicates a problem with the fuel system, specifically low fuel rail pressure. It is challenging to determine the exact cause of this problem as several factors could contribute to it. 

There are ways to eradicate this issue.

  • Inspecting the fuel rail from the fuel tank to the injector. If you notice any bends or soft spots on the rail, these could hinder your car’s fuel supply, causing low pressure in the fuel rail. 
  • If there are no bends or soft spots in your inspection, try flushing your car’s fuel rail with cleaner additives. 
  • These additives will remove any alien debris from within your vehicle’s system and solve this issue.

Final Thoughts 

Code P0087 is a significant concern for Duramax owners. It can cause various problems in your vehicle and affect its performance. You can diagnose and solve this problem effectively with the information provided in this article. Constantly monitor fuel pressure levels and take the necessary steps to maintain them optimally. Ensure to follow the recommended maintenance schedule for causes and solutions of the P0087 Duramax Code. These precautions allow you to keep your vehicle running smoothly without interruptions.

Frequently Asked Questions

What are the symptoms of low fuel rail pressure?

Low fuel rail pressure can cause a variety of symptoms in your vehicle. The most common symptom is a decrease in engine power. Another symptom is rough idling or stalling when the engine is idle.

What is a low fuel rail pressure?

Low fuel rail pressure is a condition in which the amount of pressure applied to the fuel within the fuel rail is below what is necessary for efficient combustion. It can cause an engine to run rough or stall completely. It can also lead to decreased performance and poor fuel economy.

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