5.9 Cummins Running Rough / Misfire
Several things could be causing rough running or a misfire in your 5.9L Cummins:
Problem: Mechanically failing injector(s)
A condition of running rough can be one of many factors.
If the truck runs rough when it’s cold but clears up when the engine is warm, you have a stiction issue in your injectors. Treating with Diesel Extreme will clear out the debris in your injectors.
If the truck runs rough only at idle, a stiction issue is likely, so treat this the same way.
If the truck is running rough all of the time, it can be a little more complicated. An injector may have gotten beyond the point or our product cleaning it. An injection pump may be failing, or a pump may have gotten out of time.
An electrical issue, such as a sensor failure, can affect your truck in a similar way. You will need a scan tool to properly diagnose this.
The hardest to diagnose is an intermittent miss. It may be best to take the vehicle to a professional, depending on how good you are with your vehicles electrical system.