Ford 6.4L Powerstroke Misfire / Running Rough

6.4 Powerstroke Misfire

One of the most common symptoms of a misfiring engine is rough idle. A misfire occurs when combustion fails to take place in one or more of your engine’s cylinders. Finding out the cause and repairing the problem is critical, as these issues can eventually throw your engine out of rhythm and cause it to stall.

What Causes a Misfire in Your 6.4 Powerstroke?

While a misfire usually begins as a small nuisance, your engine might not start or stop running altogether if you don’t diagnose the problem immediately. One of the most common symptoms of a misfiring engine is uneven or rough idle.

If your engine is misfiring intermittently, diagnosing the problem can be challenging. One of the most common causes of misfiring is a faulty fuel injection control module (FICM), especially if your engine is missing at speeds between 45 and 65 mph.

Using a scan tool can sometimes diagnose the problem behind the misfire right away. For additional assistance in FICM analysis, check out and follow the detailed FICM testing guide at FICMRepair.com. If everything looks good and you still can’t determine the issue, you should take your truck to a qualified mechanic for a professional diagnosis.

6.4 Powerstroke Rough Idle Causes

Rough idle in your diesel engine can result from various issues, from loss of spark to faulty injectors to inadequate compression. Some of the indicators of a rough idling engine are: 

• Inconsistent RPMs
• Shaking and skipping
• Bouncing and vibrating during idle

Some specific causes and solutions include:

Cause: Stiction inside your fuel injectors.

Solution: Treat your engine with Stiction Eliminator to restore compression and clean out your injectors. You can also apply Diesel Extreme to your fuel tank to cleanse the entire system.

Cause: Your fuel injectors are failing mechanically.

Solution: If the rough idle or misfiring continues, you’ll need to look for more severe injector or electrical issues.

6.4 Powerstroke Intermittent Rough Idle Details

A few different problems might be the cause of your engine running rough intermittently. If your engine runs fine when warm but sounds irregular when cold, you might have a stiction problem in your injectors. Using our Stiction Eliminator can be an effective way to remove the gumming.

This solution also works if your engine is running rough only at idle.

Besides treating your injectors with Stiction Eliminator, we advise cleaning your fuel system with Diesel Extreme. This process will clear out your fuel tank, lines and cylinders while eliminating moisture inside the system.

Analysis of Continuous Rough Idle in Your 6.4 Powerstroke

Diagnosing your problem might be more complex if your engine continuously runs rough. Injectors with significant stiction will sputter and spit regularly, so if stiction is indeed the cause, Stiction Eliminator should solve your problem.

Still, be prepared to take more aggressive action, as the same signs can also point to an injector that needs replacement.

An electrical issue like a failing sensor can produce similar results. In many cases, the culprit could be a faulty ICP sensor. Using your scan tool to diagnose the exact problem will help you correctly identify the issue.